On 1 April 2017 China established Xiongan New Area in Hebei Province, which was described as ‘a strategy crucial for a millennium to come'. A point of interest for the public is to be aware of the historical climate...On 1 April 2017 China established Xiongan New Area in Hebei Province, which was described as ‘a strategy crucial for a millennium to come'. A point of interest for the public is to be aware of the historical climate change in this new area; however, results from previous global-scale or largerregional-scale averages provide relatively limited information because of the distinct regional differences in climate change. This study analyzes the changes in mean and extreme temperature in this area, based on homogenized daily temperature data for the period 1960–2016. The results show a significant warming in the indices of annual, summer, and winter mean temperature(Tmean), maximum temperature(Tmax), and minimum temperature(Tmin). The linear rate of annual Tmean is 0.34 °C/decade. Temperatures on the hottest day, the warmest night, the coldest day, and the coldest night, every year, all show increasing trends, with the trends in the two nighttime-related indices being significant. An increasing occurrence of warm days, warm nights, hot days, and tropical nights, but a decreasing occurrence of cold days, cold nights, icing days, and frost days, are found, all of which are significant, except for the occurrences of hot days and icing days. A significant extension of the length of the thermal growing season is also found. The magnitudes of change in most of the temperature indices in Xiongan New Area are larger than those of the adjacent Jing-Jin-Ji and North China regional mean. These results could provide valuable information for policymakers, city planners, engineers, and migrants to this new area.展开更多
Using 4 global reanalysis data sets, significant upward trends of precipitable water vapor(PWV) were found in the 3 time periods of 1958-2020, 1979-2020, and 2000-2020. During 1958-2020, the global PWV trends obtained...Using 4 global reanalysis data sets, significant upward trends of precipitable water vapor(PWV) were found in the 3 time periods of 1958-2020, 1979-2020, and 2000-2020. During 1958-2020, the global PWV trends obtained using the ERA5 and JRA55 data sets are 0.19 ± 0.01 mm per decade(1.15 ± 0.31%)and 0.23 ± 0.01 mm per decade(1.45 ± 0.32%), respectively. The PWV trends obtained using the ERA5,JRA55, NCEP-NCAR, and NCEP-DOE data sets are 0.22 ± 0.01 mm per decade(1.18 ± 0.54%),0.21 ± 0.00 mm per decade(1.76 ± 0.56%), 0.27 ± 0.01 mm per decade(2.20 ± 0.70%) and 0.28 ± 0.01 mm per decade(2.19 ± 0.70%) for the period 1979-2020. During 2000-2020, the PWV trends obtained using ERA5, JRA55, NCEP-DOE, and NCEP-NCAR data sets are 0.40 ± 0.25 mm per decade(2.66 ± 1.51%),0.37 ± 0.24 mm per decade(2.19 ± 1.54%), 0.40 ± 0.26 mm per decade(1.96 ± 1.53%) and 0.36 ± 0.25 mm per decade(2.47 ± 1.72%), respectively. Rising PWV has a positive impact on changes in precipitation,increasing the probability of extreme precipitation and then changing the frequency of flood disasters.Therefore, exploring the relationship between PWV(derived from ERA5 and JRA55) change and flood disaster frequency from 1958 to 2020 revealed a significant positive correlation between them, with correlation coefficients of 0.68 and 0.79, respectively, which explains the effect of climate change on the increase in flood disaster frequency to a certain extent. The study can provide a reference for assessing the evolution of flood disasters and predicting their frequency trends.展开更多
1 INTRODUCTION As one of the main factors affecting input and use of precipitation by forests, rainfall also makes a difference on partitioning of gross precipitation over the canopy, equilibrium of water amount in ri...1 INTRODUCTION As one of the main factors affecting input and use of precipitation by forests, rainfall also makes a difference on partitioning of gross precipitation over the canopy, equilibrium of water amount in river basins and water cycling processes . In view of its poorlydefined four seasons in contrast to well-defined dry and wet spells in addition to its inland location, understanding of precipitation characteristics and tendencies is important for the study on local forestry hydrology. Relevant research has been documented, but few have dealt with multiple time scales at the hourly, daily, monthly and annual intervals. With the 1992 - 2003 automatic record of precipitation in Menglun, Xishuangbannan analyzed, its characteristics and trends are summarized to help in the study on forestry hydrology.展开更多
The long-term trends in the occurrence frequency of pre-summer daytime and nocturnal extreme hourly rainfall(EXHR) during 1988-2018 in Hong Kong and their spatial distributions are examined and analyzed. Despite a sig...The long-term trends in the occurrence frequency of pre-summer daytime and nocturnal extreme hourly rainfall(EXHR) during 1988-2018 in Hong Kong and their spatial distributions are examined and analyzed. Despite a significant increasing trend observed in the occurrence frequency of pre-summer EXHRs during the investigated period,the increase in daytime and nocturnal EXHRs show distinct spatial patterns. Nocturnal EXHRs show uniform increasing trends over the entire Hong Kong. However, the increase in daytime EXHRs is concentrated over the northern or eastern areas of Hong Kong, indicating a downstream shift of pre-summer EXHRs in Hong Kong with regard to the prevailing southwesterly monsoonal flows in south China. The clustering of weather types associated with daytime and nocturnal EXHRs further reveals that the increase in EXHRs over Hong Kong are mainly contributed by the increase of the events associated with southwesterly monsoonal flows with relatively high speeds. During the past few decades, the southwesterly monsoonal flows at coastal south China have undergone a substantial weakening due to the increased surface roughness induced by the urbanization over the Guangdong-Hong Kong-Macao Greater Bay Area since 1990s,leading to enhanced low-level convergence and thus significant increase in EXHRs at coastal south China. Meanwhile,daytime sea-wind circulation at coastal south China is markedly enhanced during the investigated period, which is the main reason for the northward shift of daytime EXHRs in Hong Kong. In addition, the blocked southwesterly monsoonal flows at coastal south China are detoured eastward, leading to stronger convergence and increase in EXHRs at eastern coast of Hong Kong, especially during daytime, when the easterly sea winds prevail at the region.展开更多
The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constan...The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle.展开更多
Through analyzing the yearly average data obtained from 123 regular meteorological observatories located in the Tibetan Plateau (T-P), this article studies the characteristics of climate change in T-P in the last 40 y...Through analyzing the yearly average data obtained from 123 regular meteorological observatories located in the Tibetan Plateau (T-P), this article studies the characteristics of climate change in T-P in the last 40 years. Prom the distribution of the linear trend, it can be concluded that the southeastern part of T-P becomes warmer and wetter, with an obvious increase of rainfall. The same characteristics are found in the southwestern part of T-P, but the shift is smaller. In the middle of T-P, temperature and humidity obviously increase with the center of the increase in Bangoin-Amdo. The south of the Tarim Basin also exhibits the same tendency. The reason for this area being humid is that it gets less sunshine and milder wind. The northeastern part of T-P turns warmer and drier. Qaidam Basin and its western and southern areas are the center of this shift, in which the living environment is deteriorating. Analyzing the characteristics of the regional average time series, it can be found that in the mid-1970s, a significant sudden change occurred to annual rainfall, yearly average snow-accumulation days and surface pressure in the eastern part of T-P. In the mid-1980s, another evident climatic jump happened to yearly average temperature, total cloud amount, surface pressure, relative humidity, and sunshine duration in the same area. That is, in the mid 1980s, the plateau experienced a climatic jump that is featured by the increase of temperature, snow-accumulation days, relative humidity, surface pressure, and by the decrease of sunshine duration and total cloud amount. The sudden climatic change of temperature in T-P is later than that of the global-mean temperature. Prom this paper it can be seen that in the middle of the 1980s, a climatic jump from warm-dry to warm-wet occurred in T-P.展开更多
Long-term change of sea surface temperature (SST) in the China Seas from 1900 to 2006 is examined based on two different observation datasets (HadlSSTI and HadSST3). Similar to the Atlantic, SST in the China Seas ...Long-term change of sea surface temperature (SST) in the China Seas from 1900 to 2006 is examined based on two different observation datasets (HadlSSTI and HadSST3). Similar to the Atlantic, SST in the China Seas has been well observed during the past 107 years. A comparison between the reconstructed (HadISSTI) and un-interpolated (HadSST3) datasets shows that the SST wanning trends from both datasets are consistent with each other in most of the China Seas. The warming trends are stronger in winter than in summer, with a maximum rate of SST increase exceeding 2.7℃ (100year)-I in the East China Sea and the Taiwan Strait during winter based on HadISSTI. However, the SST from both datasets experienced a sudden decrease after 1999 in the China Seas. The estimated trend from HadlSSTI is stronger than that fi'om HadSST3 in the East China Sea and the east of Taiwan Island, where the difference in the linear SST warming trends are as large as about 1℃ (100year)-I when using respectively HadISST1 and HadSST3 datasets. When compared to the linear winter warnling trend of the land surface air temperature (1.6℃ (100 year)-1), HadSST3 shows a more reasonable trend of less than 2.1℃( 100 year)-1 than HadISST 1 's trend of larger than 2.7℃ ( 100 year)-1 at the mouth of the Yangtze River. The restllts also indicate large uncertainties in the estimate of SST warming patterns.展开更多
The total precipitation of the highest 1 day, 3 day, 5 day and 7 day precipitation amount (R1 D, R3D, R5D and R7D) in the Yangtze River basin was analyzed with the help of linear trend analysis and continuous wavele...The total precipitation of the highest 1 day, 3 day, 5 day and 7 day precipitation amount (R1 D, R3D, R5D and R7D) in the Yangtze River basin was analyzed with the help of linear trend analysis and continuous wavelet transform method. The research results indicated that: 1) Spatial distribution of RID is similar in comparison with that of R3D, R5D and R7D. The Jialingjiang and Hanjiang river basins are dominated by decreasing trend, which is significant at 〉95% confidence level in Jialingjiang River basin and insignificant at 〉95% confidence level in Hanjiang River basin. The southern part of the Yangtze River basin and the western part of the upper Yangtze River basin are dominated by significant increasing trend of RID extreme precipitation at 〉95% confidence level. 2) As for the R3D, R5D and R7D, the western part of the upper Yangtze River basin is dominated by significant increasing trend at 〉95% confidence level. The eastern part of the upper Yangtze River basin is dominated by decreasing trend, but is insignificant at 〉95% confidence level. The middle and lower Yangtze River basin is dominated by increasing trend, but insignificant at 〉95% confidence level. 3) The frequency and intensity of extreme precipitation events are intensified over time. Precipitation anomalies indicated that the southeastern part, southern part and southwestern part of the Yangtze River basin are dominated by positive extreme precipitation anomalies between 1993-2002 and 1961-1992. The research results of this text indicate that the occurrence probability of flash flood is higher in the western part of the upper Yangtze River basin and the middle and lower Yangtze River basin, esp. in the southwestern and southeastern parts of the Yangtze River basin.展开更多
This paper discusses the interannual variability of the Northern Yellow Sea Cold Water Mass(NYSCWM) and the factors that influence it,based on survey data from the 1976–2006 national standard section and the Korea Oc...This paper discusses the interannual variability of the Northern Yellow Sea Cold Water Mass(NYSCWM) and the factors that influence it,based on survey data from the 1976–2006 national standard section and the Korea Oceanographic Data Center,monthly E-P flux data from the European Centre for Medium-Range Weather Forecasts,and meridional wind speed data from the International Comprehensive Ocean-Atmosphere Data Set. The results show that:1) the mean salinity of the NYSCWM center has a slightly decreasing trend,which is not consistent with the high salinity center; 2) both the southern salinity front and the halocline of the NYSCWM display a weakening trend,which indicates that the difference between the NYSCWM and coastal water decreases; 3) the Yellow Sea Warm Current intrusion,the E-P flux of the northern Yellow Sea,and the strength of the winter monsoon will affect the NYSCWM salinity during the following summer.展开更多
The low-frequency variability of the North Equatorial Current (NEC) bifurcation during 1958 to 2001 was investigated with the Simple Ocean Data Assimilation (SODA) 2.0.2 dataset. In agreement with recent observati...The low-frequency variability of the North Equatorial Current (NEC) bifurcation during 1958 to 2001 was investigated with the Simple Ocean Data Assimilation (SODA) 2.0.2 dataset. In agreement with recent observations, the NEC bifurcation latitude (NBL) shifted northward as depth increases, from about 12.7°N near the surface to about 17.1°N at depths around 500 m for the annual average. This study reveals that the interannual variations of NBL, with five years period, mainly focused on the upper 500 m with amplitude increasing as depth increased. The NBL shifted southward in the past 40 years, which was more significant in the subsurface at more than -0.02°/a. The NBL manifests itself in the transports of NMK (NEC-Mindanao Current (MC)-Kuroshio) system in strong relationship with MC (0.7) and Kuroshio (-0.7). The EOF analysis of meridional velocity off the Philippine coast shows that the first mode, explaining 62% of variance and 5 years period, was highly correlated with the southward shift of NBL with coefficient at about 0.75. The southward shift of NBL consists with the weakening of MC and strengthening of Kuroshio, which exhibited linear trends at -0.24Sv/a and 0.11Sv/a. Both interannual variation and trend of NBL were closely related to the variation of NMK system.展开更多
Marine heatwaves(MHWs)are prolonged high-temperature extreme events in the ocean that can be devastating to marine life and seriously impact climate systems and economies.This paper describes the accessibility,content...Marine heatwaves(MHWs)are prolonged high-temperature extreme events in the ocean that can be devastating to marine life and seriously impact climate systems and economies.This paper describes the accessibility,content,characteristics,and potential applications of an MHW dataset to facilitate its use in scientific research.Daily intensities of global MHWs from 1982 to 2020 were analyzed using gridded SST data sourced from the National Oceanic and Atmospheric Administration(NOAA)Optimum Interpolation(OI)SST V2 high-resolution(0.25°)dataset.The analysis shows a linear increase in the frequency of MHWs in most ocean regions of the world as well as significant interdecadal changes.This data product can be used as a basic dataset to study the seasonal to decadal changes in extreme ocean events and explore the effects of global warming on the surface layers of oceans during the last 40 years.展开更多
Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased est...Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased estimator of variance does not exist for this design.Oftentimes,a quasi-default estimator applicable to simple random sampling(SRS)is used,even if it carries with it the likely risk of overestimating the variance by a practically important margin.To better exploit the precision of systematic sampling we assess the performance of five estimators of variance,including the quasi default.In this study,simulated systematic sampling was applied to artificial populations with contrasting covariance structures and with or without linear trends.We compared the results obtained with the SRS,Matern’s,successive difference replication,Ripley’s,and D’Orazio’s variance estimators.Results:The variances obtained with the four alternatives to the SRS estimator of variance were strongly correlated,and in all study settings consistently closer to the target design variance than the estimator for SRS.The latter always produced the greatest overestimation.In populations with a near zero spatial autocorrelation,all estimators,performed equally,and delivered estimates close to the actual design variance.Conclusion:Without a linear trend,the SDR and DOR estimators were best with variance estimates more narrowly distributed around the benchmark;yet in terms of the least average absolute deviation,Matern’s estimator held a narrow lead.With a strong or moderate linear trend,Matern’s estimator is choice.In large populations,and a low sampling intensity,the performance of the investigated estimators becomes more similar.展开更多
[Objective] The aim was to analyze the changes trend of mean earth temperature at 0.8, 1.6 and 3.2 m deep to the ground in Xining from 1961 to 2010. [Method] Using the data of monthly mean soil temperatures at 0.8,1.6...[Objective] The aim was to analyze the changes trend of mean earth temperature at 0.8, 1.6 and 3.2 m deep to the ground in Xining from 1961 to 2010. [Method] Using the data of monthly mean soil temperatures at 0.8,1.6 and 3.2 m in Xining from 1961 to 2010, the linear trend, climatic anomalous and climate abrupt of deep soil temperature during recent 50 years were analyzed by using of linear trend analysis, accumulated variance and signal noise ratio methods. [Result] In terms of linear trend, the annual mean soil temperatures at 0.8 m in recent 50 years, as well as 1.6 and 3.2 m in recent 45 years displayed a weak increasing trend in Xining. Comparing with the average air temperature in the same period, the rising range of deep soil temperature is obvious less. The average soil temperatures at 0.8 m was the highest in 1980s, but it was the lowest in the 1960s. In spring, autumn and winter in the 1980s, the average soil temperature was a little higher than many other years at 1.6 m. In four seasons in the 1980s, the average soil temperature was obvious higher at 3.2 m. The annual soil temperatures at 0.8 m were anomalous warm in 1991, and from 1987 to 1992, as well as in 1994, 2007 and 2009. The annual soil temperatures at 3.2 m were anomalous warm. In the 1990s, there were four years which were anomalous warm at 3.2 m, as well as five years at 0.8 m and five years at 1.6 m. [Conclusion] The study provided theoretical basis for the development of climate changes in Xining.展开更多
Based on the daily OISST V2 with 0.25ohorizontal resolutions, the present study looks into the variations of sea surface temperature (SST) extremes in the China Seas for different segments of the period 1982-2013. The...Based on the daily OISST V2 with 0.25ohorizontal resolutions, the present study looks into the variations of sea surface temperature (SST) extremes in the China Seas for different segments of the period 1982-2013. The two segments include the warming acceleration period from 1982 to 1997 and the hiatus period from 1998 to 2013 when the global mean surface temperature (GMST) did not significantly increase as expected, or even decreased in some areas.First, we construct the regional average time series over the entire China Seas (15°-45°N, 105°-130°E) for these SST extremes. During the hiatus period, the regionally averaged 10th, 1th and 0.1th percentile of SSTs in each year decreased significantly by 0.40℃, 0.56℃ and 0.58℃ per decade, respectively. The regionally averaged 90th, 99th and 99.9th percentile of SSTs in each year decreased slightly or insignificantly. Our work confirm that the regional hiatus was primarily reflected by wintertime cold extremes. Spatially, the trends of cold extremes in different intensity were nonuniformly distributed. Cold extremes in the near-shore areas were much more sensitive to the global warming hiatus. Hot extremes exhibited non-significant trend in the China Seas during the hiatus period. In short, the variations of the SST extremes in the two periods were non-uniform spatially and asymmetric seasonally. It is unexpected that the hot and cold extremes of each year during 1998-2013 were still higher than those extremes during 1982-1997. It is obvious that compared with the warming acceleration period, hot extremes were far more likely to occur in the recent hiatus as a result of a 0.3℃ warmer shift in the mean temperature distribution. Moreover, hot extremes in the China Seas will be sustained or amplified with the end of warming hiatus and the continuous anthropogenic warming.展开更多
On the basis of the analytical results of the period components of monthly mean sea level of 236 stationsin the Pacific, the period components plus linear trend are ed to fit the monthly mean sea level series. The sta...On the basis of the analytical results of the period components of monthly mean sea level of 236 stationsin the Pacific, the period components plus linear trend are ed to fit the monthly mean sea level series. The statisticalresults of linear trend Coefficients of these stations indicate that, if the abnormal values of sea-level rise and fall are neglected, the average rise rate of relative sea level in the Pacific is 1. 16 mm/a. Affected by nonuniformity Of land subsidence and other factors, the regional change of relative sea level rise or fall in the Pacific is greater. In the light of thepositive or negative values of linear trend coefficients as well as the geographical position of the sea area, zoning is madeof the sea level rise or fall in the Pacific including the coastal areas of China and Southeast Asia to obtain the averagerate of rise or fall in each sea area. The rise or fall trends of relative sea level obtained for the entire Pacific Ocean,west coast of North America, the northern and central South America, the greater part of the tropical Pacific and thecoastal Islands of Japan are basically in keeping with the other relevant results. The regional average estimated result ofthe relative sea level in the coast of East Asia is on the rise while the estimated results provided by Barnett tend todrop; the main cause of this nonuniformity is the number of stations selected and the distributional density.展开更多
This paper summarizes the general methods,existing problems and their causes of the period analysis for the monthly mean sea level and points out that it is the key to the analysing period signals and forecasting the ...This paper summarizes the general methods,existing problems and their causes of the period analysis for the monthly mean sea level and points out that it is the key to the analysing period signals and forecasting the change trend of the monthly mean sea level that the periods of the signals are selected reasonably. As there are often many period signals in these series, nonlinear effects exist between pairs of period signals. In order to avoid the false periods that may be introduced due to the effects of side lobes and the periods with statistical phase significance coherence that may be introduced due to the effects of nonlinear effects and their restraint to other period signals, the maximum entropy spectral analysis and the corresponding significance period test may be performed repeatedly on the basis of the bispectrum analysis and meanwhile the most significant period component is filtered out by the least square filtering method, i. e., the method of the significance period analysis with mixed spectra modeled by a nonlinear system is adopted and the signal periods approaching the reality are selected one by one. The examples of the bispectrum analysis, the signal period analysis by mixed spectra and the fitting parameters for combined period components with linear trend in the time series of monthly mean sea level are given in this paper.展开更多
The new version (version 8) TOMS (Total Ozone Mapping Spectrometer) ozone and noontime erythemal ultraviolet (UV) irradiance products are used to analyze their long-term changes in this paper. It is shown that t...The new version (version 8) TOMS (Total Ozone Mapping Spectrometer) ozone and noontime erythemal ultraviolet (UV) irradiance products are used to analyze their long-term changes in this paper. It is shown that the summer UV irradiance has increased significantly from Central China to the northern and western parts of China, especially in Central China near Chongqing, Shaanxi, and Hubei provinces; whereas the UV irradiance has decreased significantly in the southern part of China, especially in South China. In July, when UV irradiance is at its maximum and hence when the most serious potential damage may happen, the results indicate an increase in the UV irradiance in Central China and the Yangtze River- Huaihe River valley and a decrease in South China and the eastern part of North China. At the same time, the total ozone amount is lower over China in summer with the most serious depletion occurring in Northeast China and Northwest China. It is found that the thinning of the ozone layer is not the main reason for the UV irradiance trend in the eastern and southern parts of China, but that the rainfall and the related cloud variations may dominate the long-term changes of the UV irradiance there. In addition, the future UV irradiance trend in China is also estimated.展开更多
The responses of the Arctic Oscillation(AO) to global black carbon(BC) and BC emitted from major regions were compared using the atmospheric general circulation model Geophysical Fluid Dynamics Laboratory(GFDL) atmosp...The responses of the Arctic Oscillation(AO) to global black carbon(BC) and BC emitted from major regions were compared using the atmospheric general circulation model Geophysical Fluid Dynamics Laboratory(GFDL) atmospheric general circulation model(AGCM) Atmospheric Model version 2.1(AM2.1). The results indicated that global BC could induce positive-phase AO responses, characterized by negative responses over the polar cap on 500 h Pa height fields, and zonal mean sea level pressure(SLP) decreasing while zonal wind increasing at 60°, with the opposite responses over midlatitudes. The AO indices distribution also shifted towards positive values. East Asian BC had similar impacts to that of global BC, while the responses to European BC were of opposite sign. South Asian BC and North American BC did not affect the AO significantly. Based on a simple linear assumption, we roughly estimated that the global BC emission increase could explain approximately 5% of the observed positive AO trend of +0.32 per decade during 1960 to 2000.展开更多
[Objectives]The aim of this paper was to reveal the changes of large livestock industry and their influence on animal husbandry economy in Guyuan City of Ningxia.[Methods]The linear trend method was employed to quanti...[Objectives]The aim of this paper was to reveal the changes of large livestock industry and their influence on animal husbandry economy in Guyuan City of Ningxia.[Methods]The linear trend method was employed to quantify the change trends of the indicators for large livestock industry,and the ridge regression model was conducted to analyze their impacts on the gross output value of animal husbandry(GOVAH).[Results]The numbers of sold and slaughtered cattle and sheep in Guyuan presented a significant upward trend,while the number for hog had a significant downward trend,during 2000-2019.The GOVAH in Guyuan and its 5 counties had increased by 2-3 times in recent 20 years,which was mainly driven by large-scale livestock breeding.The cattle and sheep breeding sectors had positive effects on GOVAH,while the hog breeding sector had negative effect.[Conclusions]This study provides a reference for the structural adjustment and large-scale development of animal husbandry.展开更多
The change of sea surface temperature(SST) in the southern Indian Ocean(SIO) during the recent six decades has been analyzed based on oceanic reanalysis and model, as well as atmospheric data. The results show tha...The change of sea surface temperature(SST) in the southern Indian Ocean(SIO) during the recent six decades has been analyzed based on oceanic reanalysis and model, as well as atmospheric data. The results show that a thermal regime shift in SIO during the 1960 s, which is not caught enough attentions, has been of equal magnitude to the linear warming since 1970. Empirical Orthogonal Function(EOF) analyses reveal that a thermal shift is combined with atmospheric changes such as the weakening of westerly during the period of 1960–1967. Inner dynamic connections can be defined that when the westerly winds turn weak, the anticyclonic wind circulation between westerly winds and the trade winds decreases, which further reduces the SST to a negative peak in this period. It is noted that the shifts in the 1960 s are also evident for Southern Hemisphere. For example, subtropical high and the entire westerly winds belt at high latitudes both change dramatically in the 1960 s. This large-scaled process maybe link to the change of southern annular mode(SAM).展开更多
基金sponsored by the National Key R&D Programof China(grant number 2016YFA0600404)Key Technology of Integration of Meteorological and Application Projects(grant number CMAGJ2015Z16)+1 种基金the Youth Innovation Promotion Association of CAS(grant number 2016075)the Jiangsu Collaborative Innovation Center for Climate Change
文摘On 1 April 2017 China established Xiongan New Area in Hebei Province, which was described as ‘a strategy crucial for a millennium to come'. A point of interest for the public is to be aware of the historical climate change in this new area; however, results from previous global-scale or largerregional-scale averages provide relatively limited information because of the distinct regional differences in climate change. This study analyzes the changes in mean and extreme temperature in this area, based on homogenized daily temperature data for the period 1960–2016. The results show a significant warming in the indices of annual, summer, and winter mean temperature(Tmean), maximum temperature(Tmax), and minimum temperature(Tmin). The linear rate of annual Tmean is 0.34 °C/decade. Temperatures on the hottest day, the warmest night, the coldest day, and the coldest night, every year, all show increasing trends, with the trends in the two nighttime-related indices being significant. An increasing occurrence of warm days, warm nights, hot days, and tropical nights, but a decreasing occurrence of cold days, cold nights, icing days, and frost days, are found, all of which are significant, except for the occurrences of hot days and icing days. A significant extension of the length of the thermal growing season is also found. The magnitudes of change in most of the temperature indices in Xiongan New Area are larger than those of the adjacent Jing-Jin-Ji and North China regional mean. These results could provide valuable information for policymakers, city planners, engineers, and migrants to this new area.
基金support from the Natural Science Foundation of Hubei Province,China (Grant No.2019CFB795)the National Natural Science Foundation of China(project 42074011)
文摘Using 4 global reanalysis data sets, significant upward trends of precipitable water vapor(PWV) were found in the 3 time periods of 1958-2020, 1979-2020, and 2000-2020. During 1958-2020, the global PWV trends obtained using the ERA5 and JRA55 data sets are 0.19 ± 0.01 mm per decade(1.15 ± 0.31%)and 0.23 ± 0.01 mm per decade(1.45 ± 0.32%), respectively. The PWV trends obtained using the ERA5,JRA55, NCEP-NCAR, and NCEP-DOE data sets are 0.22 ± 0.01 mm per decade(1.18 ± 0.54%),0.21 ± 0.00 mm per decade(1.76 ± 0.56%), 0.27 ± 0.01 mm per decade(2.20 ± 0.70%) and 0.28 ± 0.01 mm per decade(2.19 ± 0.70%) for the period 1979-2020. During 2000-2020, the PWV trends obtained using ERA5, JRA55, NCEP-DOE, and NCEP-NCAR data sets are 0.40 ± 0.25 mm per decade(2.66 ± 1.51%),0.37 ± 0.24 mm per decade(2.19 ± 1.54%), 0.40 ± 0.26 mm per decade(1.96 ± 1.53%) and 0.36 ± 0.25 mm per decade(2.47 ± 1.72%), respectively. Rising PWV has a positive impact on changes in precipitation,increasing the probability of extreme precipitation and then changing the frequency of flood disasters.Therefore, exploring the relationship between PWV(derived from ERA5 and JRA55) change and flood disaster frequency from 1958 to 2020 revealed a significant positive correlation between them, with correlation coefficients of 0.68 and 0.79, respectively, which explains the effect of climate change on the increase in flood disaster frequency to a certain extent. The study can provide a reference for assessing the evolution of flood disasters and predicting their frequency trends.
基金Development Plan for Key National Foundation Research (Project 973 and 2003CB415100)Natural Science Foundation of Yunnan Province (2003C0002Z)
文摘1 INTRODUCTION As one of the main factors affecting input and use of precipitation by forests, rainfall also makes a difference on partitioning of gross precipitation over the canopy, equilibrium of water amount in river basins and water cycling processes . In view of its poorlydefined four seasons in contrast to well-defined dry and wet spells in addition to its inland location, understanding of precipitation characteristics and tendencies is important for the study on local forestry hydrology. Relevant research has been documented, but few have dealt with multiple time scales at the hourly, daily, monthly and annual intervals. With the 1992 - 2003 automatic record of precipitation in Menglun, Xishuangbannan analyzed, its characteristics and trends are summarized to help in the study on forestry hydrology.
基金Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)Hong Kong Research Grant Council(Aoe/E-603/18)。
文摘The long-term trends in the occurrence frequency of pre-summer daytime and nocturnal extreme hourly rainfall(EXHR) during 1988-2018 in Hong Kong and their spatial distributions are examined and analyzed. Despite a significant increasing trend observed in the occurrence frequency of pre-summer EXHRs during the investigated period,the increase in daytime and nocturnal EXHRs show distinct spatial patterns. Nocturnal EXHRs show uniform increasing trends over the entire Hong Kong. However, the increase in daytime EXHRs is concentrated over the northern or eastern areas of Hong Kong, indicating a downstream shift of pre-summer EXHRs in Hong Kong with regard to the prevailing southwesterly monsoonal flows in south China. The clustering of weather types associated with daytime and nocturnal EXHRs further reveals that the increase in EXHRs over Hong Kong are mainly contributed by the increase of the events associated with southwesterly monsoonal flows with relatively high speeds. During the past few decades, the southwesterly monsoonal flows at coastal south China have undergone a substantial weakening due to the increased surface roughness induced by the urbanization over the Guangdong-Hong Kong-Macao Greater Bay Area since 1990s,leading to enhanced low-level convergence and thus significant increase in EXHRs at coastal south China. Meanwhile,daytime sea-wind circulation at coastal south China is markedly enhanced during the investigated period, which is the main reason for the northward shift of daytime EXHRs in Hong Kong. In addition, the blocked southwesterly monsoonal flows at coastal south China are detoured eastward, leading to stronger convergence and increase in EXHRs at eastern coast of Hong Kong, especially during daytime, when the easterly sea winds prevail at the region.
文摘The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle.
文摘Through analyzing the yearly average data obtained from 123 regular meteorological observatories located in the Tibetan Plateau (T-P), this article studies the characteristics of climate change in T-P in the last 40 years. Prom the distribution of the linear trend, it can be concluded that the southeastern part of T-P becomes warmer and wetter, with an obvious increase of rainfall. The same characteristics are found in the southwestern part of T-P, but the shift is smaller. In the middle of T-P, temperature and humidity obviously increase with the center of the increase in Bangoin-Amdo. The south of the Tarim Basin also exhibits the same tendency. The reason for this area being humid is that it gets less sunshine and milder wind. The northeastern part of T-P turns warmer and drier. Qaidam Basin and its western and southern areas are the center of this shift, in which the living environment is deteriorating. Analyzing the characteristics of the regional average time series, it can be found that in the mid-1970s, a significant sudden change occurred to annual rainfall, yearly average snow-accumulation days and surface pressure in the eastern part of T-P. In the mid-1980s, another evident climatic jump happened to yearly average temperature, total cloud amount, surface pressure, relative humidity, and sunshine duration in the same area. That is, in the mid 1980s, the plateau experienced a climatic jump that is featured by the increase of temperature, snow-accumulation days, relative humidity, surface pressure, and by the decrease of sunshine duration and total cloud amount. The sudden climatic change of temperature in T-P is later than that of the global-mean temperature. Prom this paper it can be seen that in the middle of the 1980s, a climatic jump from warm-dry to warm-wet occurred in T-P.
基金supported by the National Basic Research Program of China(2012-CB955602)National Key Program for Developing Basic Science(2010CB428904)Natural Science Foundation of China(40830106,40921004 and 41176006)
文摘Long-term change of sea surface temperature (SST) in the China Seas from 1900 to 2006 is examined based on two different observation datasets (HadlSSTI and HadSST3). Similar to the Atlantic, SST in the China Seas has been well observed during the past 107 years. A comparison between the reconstructed (HadISSTI) and un-interpolated (HadSST3) datasets shows that the SST wanning trends from both datasets are consistent with each other in most of the China Seas. The warming trends are stronger in winter than in summer, with a maximum rate of SST increase exceeding 2.7℃ (100year)-I in the East China Sea and the Taiwan Strait during winter based on HadISSTI. However, the SST from both datasets experienced a sudden decrease after 1999 in the China Seas. The estimated trend from HadlSSTI is stronger than that fi'om HadSST3 in the East China Sea and the east of Taiwan Island, where the difference in the linear SST warming trends are as large as about 1℃ (100year)-I when using respectively HadISST1 and HadSST3 datasets. When compared to the linear winter warnling trend of the land surface air temperature (1.6℃ (100 year)-1), HadSST3 shows a more reasonable trend of less than 2.1℃( 100 year)-1 than HadISST 1 's trend of larger than 2.7℃ ( 100 year)-1 at the mouth of the Yangtze River. The restllts also indicate large uncertainties in the estimate of SST warming patterns.
基金Funded by the Nanjing Institute of Geography and Limnology, CAS, No.S260018 The Chinese Meteoro-logical Administration, No.ccsf2006-31
文摘The total precipitation of the highest 1 day, 3 day, 5 day and 7 day precipitation amount (R1 D, R3D, R5D and R7D) in the Yangtze River basin was analyzed with the help of linear trend analysis and continuous wavelet transform method. The research results indicated that: 1) Spatial distribution of RID is similar in comparison with that of R3D, R5D and R7D. The Jialingjiang and Hanjiang river basins are dominated by decreasing trend, which is significant at 〉95% confidence level in Jialingjiang River basin and insignificant at 〉95% confidence level in Hanjiang River basin. The southern part of the Yangtze River basin and the western part of the upper Yangtze River basin are dominated by significant increasing trend of RID extreme precipitation at 〉95% confidence level. 2) As for the R3D, R5D and R7D, the western part of the upper Yangtze River basin is dominated by significant increasing trend at 〉95% confidence level. The eastern part of the upper Yangtze River basin is dominated by decreasing trend, but is insignificant at 〉95% confidence level. The middle and lower Yangtze River basin is dominated by increasing trend, but insignificant at 〉95% confidence level. 3) The frequency and intensity of extreme precipitation events are intensified over time. Precipitation anomalies indicated that the southeastern part, southern part and southwestern part of the Yangtze River basin are dominated by positive extreme precipitation anomalies between 1993-2002 and 1961-1992. The research results of this text indicate that the occurrence probability of flash flood is higher in the western part of the upper Yangtze River basin and the middle and lower Yangtze River basin, esp. in the southwestern and southeastern parts of the Yangtze River basin.
基金Supported by the National Natural Science Foundation of China(Nos.41176018,41376031)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA11020301)the NSFC-Shandong Joint Fund for Marine Science Research Centers(No.U1406401)
文摘This paper discusses the interannual variability of the Northern Yellow Sea Cold Water Mass(NYSCWM) and the factors that influence it,based on survey data from the 1976–2006 national standard section and the Korea Oceanographic Data Center,monthly E-P flux data from the European Centre for Medium-Range Weather Forecasts,and meridional wind speed data from the International Comprehensive Ocean-Atmosphere Data Set. The results show that:1) the mean salinity of the NYSCWM center has a slightly decreasing trend,which is not consistent with the high salinity center; 2) both the southern salinity front and the halocline of the NYSCWM display a weakening trend,which indicates that the difference between the NYSCWM and coastal water decreases; 3) the Yellow Sea Warm Current intrusion,the E-P flux of the northern Yellow Sea,and the strength of the winter monsoon will affect the NYSCWM salinity during the following summer.
基金supported by the National Natural Science Foundation of China under contract No.NSFC40890152the Knowledge Innovation Program of Chinese Academy of Sciences under contract No.KZCX2-YW-Q11-02
文摘The low-frequency variability of the North Equatorial Current (NEC) bifurcation during 1958 to 2001 was investigated with the Simple Ocean Data Assimilation (SODA) 2.0.2 dataset. In agreement with recent observations, the NEC bifurcation latitude (NBL) shifted northward as depth increases, from about 12.7°N near the surface to about 17.1°N at depths around 500 m for the annual average. This study reveals that the interannual variations of NBL, with five years period, mainly focused on the upper 500 m with amplitude increasing as depth increased. The NBL shifted southward in the past 40 years, which was more significant in the subsurface at more than -0.02°/a. The NBL manifests itself in the transports of NMK (NEC-Mindanao Current (MC)-Kuroshio) system in strong relationship with MC (0.7) and Kuroshio (-0.7). The EOF analysis of meridional velocity off the Philippine coast shows that the first mode, explaining 62% of variance and 5 years period, was highly correlated with the southward shift of NBL with coefficient at about 0.75. The southward shift of NBL consists with the weakening of MC and strengthening of Kuroshio, which exhibited linear trends at -0.24Sv/a and 0.11Sv/a. Both interannual variation and trend of NBL were closely related to the variation of NMK system.
基金the Key Research Program of Frontier Sciences,CAS(Grant No.ZDBS-LY-DQC010)the National Natural Science Foundation of China(Grant No.41876012)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB42000000)the National Key R&D Program of China 2018YFB0505000.NOAA High-Resolution SST data were provided by the NOAA/OAR/ESRL PSD,Boulder,Colorado,USA,from their Web site at http://www.esrl.noaa.gov/psd/.The authors wish to thank two anony-mous reviewers for their very helpful comments and suggestions.
文摘Marine heatwaves(MHWs)are prolonged high-temperature extreme events in the ocean that can be devastating to marine life and seriously impact climate systems and economies.This paper describes the accessibility,content,characteristics,and potential applications of an MHW dataset to facilitate its use in scientific research.Daily intensities of global MHWs from 1982 to 2020 were analyzed using gridded SST data sourced from the National Oceanic and Atmospheric Administration(NOAA)Optimum Interpolation(OI)SST V2 high-resolution(0.25°)dataset.The analysis shows a linear increase in the frequency of MHWs in most ocean regions of the world as well as significant interdecadal changes.This data product can be used as a basic dataset to study the seasonal to decadal changes in extreme ocean events and explore the effects of global warming on the surface layers of oceans during the last 40 years.
文摘Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased estimator of variance does not exist for this design.Oftentimes,a quasi-default estimator applicable to simple random sampling(SRS)is used,even if it carries with it the likely risk of overestimating the variance by a practically important margin.To better exploit the precision of systematic sampling we assess the performance of five estimators of variance,including the quasi default.In this study,simulated systematic sampling was applied to artificial populations with contrasting covariance structures and with or without linear trends.We compared the results obtained with the SRS,Matern’s,successive difference replication,Ripley’s,and D’Orazio’s variance estimators.Results:The variances obtained with the four alternatives to the SRS estimator of variance were strongly correlated,and in all study settings consistently closer to the target design variance than the estimator for SRS.The latter always produced the greatest overestimation.In populations with a near zero spatial autocorrelation,all estimators,performed equally,and delivered estimates close to the actual design variance.Conclusion:Without a linear trend,the SDR and DOR estimators were best with variance estimates more narrowly distributed around the benchmark;yet in terms of the least average absolute deviation,Matern’s estimator held a narrow lead.With a strong or moderate linear trend,Matern’s estimator is choice.In large populations,and a low sampling intensity,the performance of the investigated estimators becomes more similar.
基金Supported by National Natural Science Fund (41075066)
文摘[Objective] The aim was to analyze the changes trend of mean earth temperature at 0.8, 1.6 and 3.2 m deep to the ground in Xining from 1961 to 2010. [Method] Using the data of monthly mean soil temperatures at 0.8,1.6 and 3.2 m in Xining from 1961 to 2010, the linear trend, climatic anomalous and climate abrupt of deep soil temperature during recent 50 years were analyzed by using of linear trend analysis, accumulated variance and signal noise ratio methods. [Result] In terms of linear trend, the annual mean soil temperatures at 0.8 m in recent 50 years, as well as 1.6 and 3.2 m in recent 45 years displayed a weak increasing trend in Xining. Comparing with the average air temperature in the same period, the rising range of deep soil temperature is obvious less. The average soil temperatures at 0.8 m was the highest in 1980s, but it was the lowest in the 1960s. In spring, autumn and winter in the 1980s, the average soil temperature was a little higher than many other years at 1.6 m. In four seasons in the 1980s, the average soil temperature was obvious higher at 3.2 m. The annual soil temperatures at 0.8 m were anomalous warm in 1991, and from 1987 to 1992, as well as in 1994, 2007 and 2009. The annual soil temperatures at 3.2 m were anomalous warm. In the 1990s, there were four years which were anomalous warm at 3.2 m, as well as five years at 0.8 m and five years at 1.6 m. [Conclusion] The study provided theoretical basis for the development of climate changes in Xining.
基金Natural Science Foundation of China (41675046)Key-Area Research and Development Program of Guangdong Province (2020B1111020005)Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)(GML2019ZD0604)。
文摘Based on the daily OISST V2 with 0.25ohorizontal resolutions, the present study looks into the variations of sea surface temperature (SST) extremes in the China Seas for different segments of the period 1982-2013. The two segments include the warming acceleration period from 1982 to 1997 and the hiatus period from 1998 to 2013 when the global mean surface temperature (GMST) did not significantly increase as expected, or even decreased in some areas.First, we construct the regional average time series over the entire China Seas (15°-45°N, 105°-130°E) for these SST extremes. During the hiatus period, the regionally averaged 10th, 1th and 0.1th percentile of SSTs in each year decreased significantly by 0.40℃, 0.56℃ and 0.58℃ per decade, respectively. The regionally averaged 90th, 99th and 99.9th percentile of SSTs in each year decreased slightly or insignificantly. Our work confirm that the regional hiatus was primarily reflected by wintertime cold extremes. Spatially, the trends of cold extremes in different intensity were nonuniformly distributed. Cold extremes in the near-shore areas were much more sensitive to the global warming hiatus. Hot extremes exhibited non-significant trend in the China Seas during the hiatus period. In short, the variations of the SST extremes in the two periods were non-uniform spatially and asymmetric seasonally. It is unexpected that the hot and cold extremes of each year during 1998-2013 were still higher than those extremes during 1982-1997. It is obvious that compared with the warming acceleration period, hot extremes were far more likely to occur in the recent hiatus as a result of a 0.3℃ warmer shift in the mean temperature distribution. Moreover, hot extremes in the China Seas will be sustained or amplified with the end of warming hiatus and the continuous anthropogenic warming.
文摘On the basis of the analytical results of the period components of monthly mean sea level of 236 stationsin the Pacific, the period components plus linear trend are ed to fit the monthly mean sea level series. The statisticalresults of linear trend Coefficients of these stations indicate that, if the abnormal values of sea-level rise and fall are neglected, the average rise rate of relative sea level in the Pacific is 1. 16 mm/a. Affected by nonuniformity Of land subsidence and other factors, the regional change of relative sea level rise or fall in the Pacific is greater. In the light of thepositive or negative values of linear trend coefficients as well as the geographical position of the sea area, zoning is madeof the sea level rise or fall in the Pacific including the coastal areas of China and Southeast Asia to obtain the averagerate of rise or fall in each sea area. The rise or fall trends of relative sea level obtained for the entire Pacific Ocean,west coast of North America, the northern and central South America, the greater part of the tropical Pacific and thecoastal Islands of Japan are basically in keeping with the other relevant results. The regional average estimated result ofthe relative sea level in the coast of East Asia is on the rise while the estimated results provided by Barnett tend todrop; the main cause of this nonuniformity is the number of stations selected and the distributional density.
文摘This paper summarizes the general methods,existing problems and their causes of the period analysis for the monthly mean sea level and points out that it is the key to the analysing period signals and forecasting the change trend of the monthly mean sea level that the periods of the signals are selected reasonably. As there are often many period signals in these series, nonlinear effects exist between pairs of period signals. In order to avoid the false periods that may be introduced due to the effects of side lobes and the periods with statistical phase significance coherence that may be introduced due to the effects of nonlinear effects and their restraint to other period signals, the maximum entropy spectral analysis and the corresponding significance period test may be performed repeatedly on the basis of the bispectrum analysis and meanwhile the most significant period component is filtered out by the least square filtering method, i. e., the method of the significance period analysis with mixed spectra modeled by a nonlinear system is adopted and the signal periods approaching the reality are selected one by one. The examples of the bispectrum analysis, the signal period analysis by mixed spectra and the fitting parameters for combined period components with linear trend in the time series of monthly mean sea level are given in this paper.
基金This work was supported by the Chinese Key Developing Program for Basic Sciences (Grant No. 2004CB418303) the National Natural Science Foundation of China (Grant Nos. 40375021 and 40575026).
文摘The new version (version 8) TOMS (Total Ozone Mapping Spectrometer) ozone and noontime erythemal ultraviolet (UV) irradiance products are used to analyze their long-term changes in this paper. It is shown that the summer UV irradiance has increased significantly from Central China to the northern and western parts of China, especially in Central China near Chongqing, Shaanxi, and Hubei provinces; whereas the UV irradiance has decreased significantly in the southern part of China, especially in South China. In July, when UV irradiance is at its maximum and hence when the most serious potential damage may happen, the results indicate an increase in the UV irradiance in Central China and the Yangtze River- Huaihe River valley and a decrease in South China and the eastern part of North China. At the same time, the total ozone amount is lower over China in summer with the most serious depletion occurring in Northeast China and Northwest China. It is found that the thinning of the ozone layer is not the main reason for the UV irradiance trend in the eastern and southern parts of China, but that the rainfall and the related cloud variations may dominate the long-term changes of the UV irradiance there. In addition, the future UV irradiance trend in China is also estimated.
基金jointly supported by the National Basic Research Program of China(973 Program,2015CB453202 and 2012CB417403)the National Natural Science Foundation of China(41421004)
文摘The responses of the Arctic Oscillation(AO) to global black carbon(BC) and BC emitted from major regions were compared using the atmospheric general circulation model Geophysical Fluid Dynamics Laboratory(GFDL) atmospheric general circulation model(AGCM) Atmospheric Model version 2.1(AM2.1). The results indicated that global BC could induce positive-phase AO responses, characterized by negative responses over the polar cap on 500 h Pa height fields, and zonal mean sea level pressure(SLP) decreasing while zonal wind increasing at 60°, with the opposite responses over midlatitudes. The AO indices distribution also shifted towards positive values. East Asian BC had similar impacts to that of global BC, while the responses to European BC were of opposite sign. South Asian BC and North American BC did not affect the AO significantly. Based on a simple linear assumption, we roughly estimated that the global BC emission increase could explain approximately 5% of the observed positive AO trend of +0.32 per decade during 1960 to 2000.
基金Ningxia Key Research and Development Program(Special Talents)(2020BEB04028)(2019BEB04040).
文摘[Objectives]The aim of this paper was to reveal the changes of large livestock industry and their influence on animal husbandry economy in Guyuan City of Ningxia.[Methods]The linear trend method was employed to quantify the change trends of the indicators for large livestock industry,and the ridge regression model was conducted to analyze their impacts on the gross output value of animal husbandry(GOVAH).[Results]The numbers of sold and slaughtered cattle and sheep in Guyuan presented a significant upward trend,while the number for hog had a significant downward trend,during 2000-2019.The GOVAH in Guyuan and its 5 counties had increased by 2-3 times in recent 20 years,which was mainly driven by large-scale livestock breeding.The cattle and sheep breeding sectors had positive effects on GOVAH,while the hog breeding sector had negative effect.[Conclusions]This study provides a reference for the structural adjustment and large-scale development of animal husbandry.
基金The National Natural Science Foundation of China for Distinguished Young Scholars and Innovative Research Groups under contract Nos 41525019 and 41521005the Project of the State Oceanic Administration of China for Global Climate Change under contract No.GASI-IPOVAI-02the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘The change of sea surface temperature(SST) in the southern Indian Ocean(SIO) during the recent six decades has been analyzed based on oceanic reanalysis and model, as well as atmospheric data. The results show that a thermal regime shift in SIO during the 1960 s, which is not caught enough attentions, has been of equal magnitude to the linear warming since 1970. Empirical Orthogonal Function(EOF) analyses reveal that a thermal shift is combined with atmospheric changes such as the weakening of westerly during the period of 1960–1967. Inner dynamic connections can be defined that when the westerly winds turn weak, the anticyclonic wind circulation between westerly winds and the trade winds decreases, which further reduces the SST to a negative peak in this period. It is noted that the shifts in the 1960 s are also evident for Southern Hemisphere. For example, subtropical high and the entire westerly winds belt at high latitudes both change dramatically in the 1960 s. This large-scaled process maybe link to the change of southern annular mode(SAM).