Analysis of Summer Cold Vortex Activity Anomalies in Northeastern China and Their Relationship with Regional Precipitation and Temperature

The Northeastern China cold vortex(NCCV)is one type of strong cyclonic vortex that occurs near Northeastern China(NEC),and NCCV activities are typically accompanied by a series of hazardous weather.This paper employed an automatic algorithm to identify the NCCVs from 1979 to 2018 and analyzed their circulation patterns and climatic impacts by using the defined NCCV intensity index(NCCVI).The analysis revealed that the NCCV activities in summer exhibited a strong inter-annual variability,with an obvious periodicity of 3-4 years and 6-7 years,but without significant trends.In years when the NCCVI was high,NEC experienced negative geopotential height anomalies,cyclonic circulation,and cooler temperature anomalies,which were conducive to the maintenance and development of NCCV activities.Furthermore,large amounts of water vapor converged in NEC through two transportation routes as the NCCVs intensified,leading to a significant positive(negative)correlation with the summer precipitation(surface temperature)in NEC.The Atlantic sea surface temperature(SST)anomalies were closely related to summer NCCV activities.As the Atlantic SST rose,large amounts of surface sensible and latent heat flux were transported into the lower troposphere,inducing a positive geopotential height anomaly that occurred on the east side of the heat source.As a result,an eastward diverging flow was formed in the upper troposphere and propagated downstream,i.e.,the eastward propagating Rossby wave train,which eventually led to a coupled circulation in the Ural Mountains and NEC,as well as more intensive NCCV activities in summer.

The clutch size,incubation behavior of Reeves’s Pheasant(Syrmaticus reevesii) and their responses to ambient temperature and precipitation

Weather conditions play a pivotal role in embryo development and parental incubation costs,potentially impacting the clutch size and incubation behavior of birds.Understanding these effects is crucial for bird conservation.Reeves’ s Pheasant(Syrmaticus reevesii) is a threatened species endemic to China,which is characterized by female-only incubation.However,there is a lack of information regarding the impact of weather conditions on clutch size and incubation behavior in this species.Using satellite tracking,we tracked 27 wild female Reeves’ s Pheasants from 2020 to 2023 in Hubei Province,China.We explored their clutch size and incubation behavior,as well as their responses to ambient temperature and precipitation.Clutch size averaged 7.75 ±1.36,had an association with average ambient temperature and average daily precipitation during the egglaying period,and was potentially linked to female breeding attempts.Throughout the incubation period,females took an average of 0.73 ±0.46 recesses every 24 h,with an average recess duration of 100.80 ±73.37 min and an average nest attendance of 92.98 ±5.27%.They showed a unimodal recess pattern in which nest departures peaked primarily between 13:00 and 16:00.Furthermore,females rarely left nests when daily precipitation was high.Recess duration and nest attendance were influenced by the interaction between daily mean ambient temperature and daily precipitation,as well as day of incubation.Additionally,there was a positive correlation between clutch size and recess duration.These results contribute valuable insights into the lifehistory features of this endangered species.

Changes in snow cover extent in the Central Taurus Mountains from 1981 to 2021 in relation to temperature, precipitation, and atmospheric teleconnections

The snow cover over the Taurus Mountains affects water supply, agriculture, and hydropower generation in the region. In this study, we analyzed the monthly Snow Cover Extent(SCE) from November to April in the Central Taurus Mountains(Bolkar, Aladaglar, Tahtali and Binboga Mountains) from 1981 to 2021. Linear trends of snow cover season(November to April) over the last 41 years showed decreases in SCE primarily at lower elevations. The downward trend in SCE was found to be more pronounced and statistically significant for only November and March. SCE in the Central Taurus Mountains has declined about-6.3% per decade for 2500-3000 m in November and about-6.0% per decade for 1000-1500 m and 3000+ m in March over the last 41 years. The loss of SCE has become evident since the 2000s, and the lowest negative anomalies in SCE have been observed in 2014, 2001, and 2007 in the last 41 years, which are consistent with an increase in air temperature and decreased precipitation. SCE was correlated with both mean temperature and precipitation, with temperature having a greater relative importance at all elevated gradients. Results showed that there is a strong linear relationship between SCE and the mean air temperature(r =-0.80) and precipitation(r = 0.44) for all elevated gradients during the snow season. The Arctic Oscillation(AO), the North Atlantic Oscillation(NAO), and the Mediterranean Oscillation(MO) winter indices were used to explain the year-to-year variability in SCE over the Central Taurus Mountains. The results showed that the inter-annual variability observed in the winter SCE on the Central Taurus Mountains was positively correlated with the phases of the winter AO, NAO and MO, especially below 2000 m elevation.

Evaluation of the Climate Prediction System CMA-CPSv3 on Performances of Precipitation and Temperature Prediction over the Tibetan Plateau

In order to evaluate the prediction performances of the climate prediction system developed by the China Meteorological Administration (CMA-CPSv3) over the Tibetan Plateau region, the precipitation and temperature predicted by CMA-CPSv3 at different lead time was evaluated for the period of 2001-2023, by comparing with observations—the monthly precipitation of the CMAP and 2 m temperature data of the NCEP/DOE reanalysis data. The main conclusions were as follows: 1) the forecast skill of the model is very sensitive to the initial conditions and value, and the model forecast capability decreases rapidly as the lead time is extended. 2) CPSv3 performed well in capturing the spatial distribution of precipitation over Tibet in January, August, October, November and December at 0-month lead, and the forecast skill is relatively poor in March and April. CPSv3 has better performance in the east-central part of the land in January, in the central and western part of the region in March, in the whole region in April, in the northern part of Nagchu, northern part of Chamdo and central part of Shigatse in July, in the eastern part of Chamdo, northern part of Nagchu and northern part of Ali in August, in the whole region in September, and in the cities of Shigatse and Shannan in November. 3) At each lead time, the forecast skill for 2-m temperatures was higher than that for precipitation. For 2-m temperature, CPSv3 performed best in January, May, July, August, September, October, and December, while performing relatively poor in March, April, and November. Specifically, the prediction skill is higher in January and December for most of the regions, for Shigatse and Ali in May, for southern Shannan in July, and for northern Nagchu and southern Shannan in August, and there is some prediction skill in March, April and October, while CPSv3 performed poorly in November.

Synergistic Contribution of Precipitation Anomalies over Northwestern India and the South China Sea to High Temperature over the Yangtze River Valley

This study explores the characteristics of high temperature anomalies over eastern China and associated influencing factors using observations and model outputs.Results show that more long-duration（over 8 days） high temperature events occur over the middle and lower reaches of the Yangtze River Valley（YRV） than over the surrounding regions,and control most of the interannual variation of summer mean temperature in situ.The synergistic effect of summer precipitation over the South China Sea（SCS） region（18°–27°N,115°–124°E） and the northwestern India and Arabian Sea（IAS） region（18°–27°N,60°–80°E） contributes more significantly to the variation of summer YRV temperature,relative to the respective SCS or IAS precipitation anomaly.More precipitation（enhanced condensational heating） over the SCS region strengthens the western Pacific subtropical high（WPSH） and simultaneously weakens the westerly trough over the east coast of Asia,and accordingly results in associated high temperature anomalies over the YRV region through stimulating an East Asia–Pacific（EAP） pattern.More precipitation over the IAS region further adjusts the variations of the WPSH and westerly trough,and eventually reinforces high temperature anomalies over the YRV region.Furthermore,the condensational heating related to more IAS precipitation can adjust upper-tropospheric easterly anomalies over the YRV region by exciting a circumglobal teleconnection,inducing cold horizontal temperature advection and related anomalous descent,which is also conducive to the YRV high temperature anomalies.The reproduction of the above association in the model results indicates that the above results can be explained both statistically and dynamically.

Evaluation of spatiotemporal variability of temperature and precipitation over the Karakoram Highway region during the cold season by a Regional Climate Model

Precipitation and temperature are two important factors associated to snow hazards which block the transport infrastructure and cause loss of life and properties in the cold season.The in-situ observations are limited in the alpine with complex topographic characteristics,while coarse satellite rainfall estimates,reanalysis rain datasets,and gridded in-situ rain gauge datasets obscure the understanding of the precipitation patterns in hazardprone areas.Considering the Karakoram Highway(KKH)region as a study area,a double nestedWeather Research and Forecasting(WRF)model with the high resolution of a 10-km horizontal grid was performed to investigate the spatial and temporal patterns of temperature and precipitation covering the Karakoram Highway region during the cold season.The results of WRF were compared with the in-situ observations and Multi-Source WeightedEnsemble Precipitation(MSWEP)datasets.The results demonstrated that the WRF model well reproduced the observed monthly temperature(R=0.96,mean bias=-3.92°C)and precipitation(R=0.57,mean bias=8.69 mm).The WRF model delineated the essential features of precipitation variability and extremes,although it overestimatedthe wet day frequency and underestimated the precipitation intensity.Two rain bands were exhibited in a northwest-to-southeast direction over the study area.High wet day frequency was found in January,February,and March in the section between Hunza and Khunjerab.In addition,the areas with extreme values are mainly located in the Dasu-Islamabad section in February,March,and April.The WRF model has the potential to compensate for the spatial and temporal gaps of the observational networks and to provide more accurate predictions on the meteorological variables for avoiding common coldweather hazards in the ungauged and high altitude areas at a regional scale.

Long-term variability of air temperature and precipitation conditions in the Polish Carpathians

Mountain regions are sensitive to climate changes, which make them good indicators of climate change. The aim of this study is to investigate the spatial and temporal variability of air temperature and precipitation in the Polish Carpathians. This study consists of climatological analyses for the historical period 1851-2010 and future projections for 2021-2100. The results confirm that there has been significant warming of the area and that this warming has been particularly pronounced over the last few decades and will continue in the oncoming years.Climate change is most evident in the foothills;however, these are the highest summits which have experienced the most intensive increases in temperature during the recent period. Precipitation does not demonstrate any substantial trend and has high year-to-year variability. The distribution of the annual temperature contour lines modelled for selected periods provides evidence of the upward shift of vertical climate zones in the Polish Carpathians,which reach approximately 350 meters, on average,what indicates further ecological consequences as ecosystems expand or become extinct and when there are changes in the hydrological cycle.

Analysis on the Correlated Characteristics between Spring Precipitation in the Arid Region of Northwest China and Global Sea Surface Temperature

[Objective] The research aimed to study the correlated characteristics between spring precipitation in the arid region of Northwest China and global sea surface temperature. [Method] Based on GPCP global monthly precipitation data and NOAA ERSST sea surface temperature data during 1979-2008, the precipitation characteristics in the arid region of Northwest China in 30 years and its correlated distribution characteristics with the global sea surface temperature were analyzed by using the correlation and composite analysis methods. [Result] Spring rainfall presented the fluctuation increasing in the arid region of Northwest China during 1979-2008. The sea surface temperature of Indian Ocean in 15° S-22° N, 45°-105° E had the continuous influence on spring precipitation in the arid region of Northwest China. It could be as a stable factor for forecasting spring precipitation in the arid region zone of Northwest China. When the sea surface temperature was higher in Indian Ocean, Bay of Bengal and Arabian Sea, maybe spring precipitation in the arid region of Northwest China was more. If the sea surface temperature in the equatorial Eastern Pacific Ocean in prior summer, autumn and winter was higher, it was favorable for spring precipitation in the arid region of Northwest China in the next year. The sea surface temperature field in Arabian Sea, Central Indian Ocean and Western Pacific Ocean was the key factor which affected spring precipitation in the arid region of Northwest China. [Conclusion] The research provided the theory basis for the prediction and forecast of precipitation in the arid region.

Changes in the Covariability of Surface Air Temperature and Precipitation over East Asia Associated with Climate Shift in the Late 1970s

Variations in surface air temperature and precipitation are closely associated because of their thermodynamic relations. The climate shift in the late 1970s and associated changes in precipitation over East Asia have been well reported. However, how the covariability of surface air temperature and precipitation responds to the climate shift is not yet well understood. We used the observed mean（Tmean）, daily maximum（Tmax）, and minimum（Tmin） surface air temperatures and precipitation during the period of 1953–2000 to explore this issue. Results show that the covariability between Tmean and precipitation experienced remarkable changes over certain areas of East Asia after the climate shift with evident seasonal dependencies. In winter, after the climate shift significantly negative correlations occupied more areas over Mongolia and China. By contrast, in summer after the climate shift significantly negative correlations which existed over almost entire East Asia during the pre-shift period were mostly weakened with the exception of enhanced correlations over some small isolated areas. Changes in the covariability of Tmax and precipitation showed a similar spatial pattern to that of the Tmean, whereas the Tmin-precipitation covariability did not. In winter, after the climate shift positive correlations between Tmin and precipitation over southern China were largely weakened, while the areas with significantly negative correlations increased over Mongolia. In summer, changes in Tmin-precipitation covariability appeared to be a negative-positive-negative pattern from south to north over East Asia, with positive changes occurring in the Yangtze-Huai River valley and Korea and negative changes occurring over South China and Japan, and northern part of East Asia.

Effects of land use/cover change(LUCC) on the spatiotemporal variability of precipitation and temperature in the Songnen Plain,China

Understanding the effects of land use/cover change(LUCC) on regional climate is critical for achieving land use system sustainability and global climate change mitigation. However, the quantitative analysis of the contribution of LUCC to the changes of climatic factors, such as precipitation & temperature(P&T), is lacking. In this study, we combined statistical methods and the gravity center model simulation to quantify the effects of long-term LUCC on P&T in the Songnen Plain(SNP) of Northeast China from 1980–2018. The results showed the spatiotemporal variability of LUCC. For example, paddy field had the largest increase(15 166.43 km2) in the SNP, followed by dry land, while wetland had the largest decrease(19 977.13 km;) due to the excessive agricultural utilization and development. Annual average precipitation decreased at a rate of –9.89 mm per decade, and the warming trends were statistically significant with an increasing rate of 0.256°C per decade in this region since 1980. The model simulation revealed that paddy field, forestland, and wetland had positive effects on precipitation, which caused their gravity centers to migrate towards the same direction accompanied by the center of precipitation gravity, while different responses were seen for building land, dry land and unused land. These results indicated that forestland had the largest influence on the increase of precipitation compared with the other land use types.The responses in promoting the temperature increase differed significantly, being the highest in building land, and the lowest in forestland. In general, the analysis of regional-scale LUCC showed a significant reduction of wetland, and the increases in building land and cropland contributed to a continuous drying and rapid warming in the SNP.

Discontinuous Precipitation and Dissolution in Cu-4, 6 at% In Alloy under the Effect of Plastic Deformation and the Temperature

The study of the discontinuous precipitation reaction and the lamellar precipitate dissolution in the alloy Cu-In system provoked a considerable benefit and has been the subject of many theoretical and experimental investigations. The aim of this work is to make the evidence on the one hand the effect of the plastic deformation on the mechanism of the discontinuous precipitation reaction such as nucleation, growth and lamellar coarsening and in other hand the effect of temperature on the characteristics and front behavior movement of the opposite reaction (discontinuous dissolution). Different techniques of analysis have been used in this respect such as the optical microscopy, the differential thermal analysis and the microhardness Vickers. The obtained results confirm various works achieved in this field.

Discontinuous Precipitation and Dissolution under the Influence of the Plastic Strain and Temperature in Al-15 at.%Zn and Al-30 at.%Zn Alloys

The discontinuous precipitation and dissolution in the alloy Al-Zn system has been the subject of many theoretical and experimental investigations that have contributed to the understanding of the different mechanisms which control them. However, many questions remain unanswered because of the complexity of the constituted phases which are affected by the speed of the quenched, deformation, the temperature of homogenization and ageing effect. The purpose of this work is to clarify the effect of temperature and deformation on the mechanisms of these two reactions during ageing of Al-15 at.% Zn and Al-30 at.% Zn alloy. The techniques of analysis used in this respect are the optical microscopy, the X-ray diffraction and the hardness Vickers.

The Variation of Extreme Temperature and Precipitation in Shandong Province during 1961-2008

We drew on data of daily average temperature,average maximum temperature,average minimum temperature and precipitation from 78 meteorological stations during 1961-2008 of Shandong Province,analyzed the variation of extreme temperature and precipitation events.The results showed that although extreme cold days decreased by 0.23 d/a on average,after the average temperature steadily passed 10 ℃ in spring,it would still appear 1-2 days of frost,wheat and fruit trees would still suffer frozen injury every year in the central Shandong and the inland of Shandong Peninsula.Although the number of annual extreme hot days has an increasing trend obviously in Shandong and increased by 0.19 days a year.After 2000,aimed at the days of daily maximum temperature ≥ 35 ℃,the mean value and standard deviation of daily maximum temperature in summer decreased comparing with the normal year in West Shandong,and decreased by 1-3 days.In recent 50 years,the extreme precipitation trend increased,but not statistically significant.The number of light rain days has a decreasing trend and decreased by 0.17 days every year,in contrast,the frequency of downpour has an increasing trend.

The Singular Value Decomposition Analysis between Summer Precipitation in the Dongting Lake Region and the Global Sea Surface Temperature

By dint of the summer precipitation data from 21 stations in the Dongting Lake region during 1960-2008 and the sea surface temperature(SST) data from NOAA,the spatial and temporal distributions of summer precipitation and their correlations with SST are analyzed.The coupling relationship between the anomalous distribution in summer precipitation and the variation of SST has between studied with the Singular Value Decomposition(SVD) analysis.The increase or decrease of summer precipitation in the Dongting Lake region is closely associated with the SST anomalies in three key regions.The variation of SST in the three key regions has been proved to be a significant previous signal to anomaly of summer rainfall in Dongting region.

Shallow Discussion about the Application of L-band Sounding Seconds Data in the Artificial Precipitation

[Objective] The research aimed to discuss shallowly the application of L-band sounding seconds data in the artificial precipitation. [Method] The characteristics, getting manner and displaying method of L-band sounding seconds data were introduced briefly. Moreover, its application prospect in the artificial precipitation operation was analyzed initially. We aimed to improve its application rate in the artificial precipitation operation. [Result] L-band sounding seconds data had the great improvement in the time-space resolution and the space positioning accuracy aspects when compared with the previous sounding data, and the precision reached the second level. It could provide the high-precision data basis for the assimilation of artificial precipitation numerical model initial field, and improve the numerical model. Moreover, the sounding product could provide the accurate scientific basis for the selection of artificial precipitation operation tool, the determination of operation height and range, and guide the artificial precipitation operation, and improve the operation efficiency. [Conclusion] The research provided the analysis and reference basis for the command of artificial precipitation operation.

Effects of Land Surface Temperature on the Frequency of Convective Precipitation in the Tokyo Area

This study uses statistical evaluation by correlation analysis to examine the effects of thermal environment on the frequency of convective precipitation in the Greater Tokyo Area between 12:00 and 18:00 on summer days from 1997 to 2006. To extract the frequency of convective precipitation we used Automated Meteorological Data Acquisition System radar data to obtain detailed rainfall distribution maps, and to extract the urban thermal environment we used surface temperature data from a National Oceanic and Atmospheric Administration weather satellite. Results were a coefficient of determination of 0.01, indicating no clear relation between surface temperature and convective rain frequency in the study area. Examining the convective rain frequency distribution map in conjunction with an elevation map of the area indicates that higher elevation is a better predictor of increased frequency of convective rainfall than is surface temperature. Because this indicates that orographic precipitation has a large influence in the study area, we used an elevation map to exclude hilly and mountainous regions, regions bordering flat areas (under the assumption that wind could easily move orographic precipitation to such areas), and regions containing marine areas. Doing so resulted in a coefficient of determination of 0.38, a clear signal that differences in the thermal environment in the Greater Tokyo Area have an effect on the frequency of convective precipitation. We next focused on metropolitan Tokyo, the most developed part of the region and the part experiencing the most frequent occurrences of convective precipitation, and we performed correlation analysis considering parameters related to buildings. Results indicate that orographic precipitation has a strong influence in metropolitan Tokyo as well, so we excluded those areas that were excluded from the Greater Tokyo Area analysis and again performed correlation analysis. However, we found no clear relation of convective precipitation frequency with surface temperature or building parameters.

Study on the Characteristics of Changes in Air Temperature and Precipitation in Shenyang in Recent 50 Years

Based on the data of monthly average air temperature,extreme maximum,minimum air temperature and precipitation of Shenyang from 1960 to 2009,the climate changes and its characteristics in Shenyang in recent 50 years were comprehensively analyzed and studied.The results showed that the increasing trend of air temperature in recent 50 years was obvious.With the rising of the air temperature,the precipitation in Shenyang City showed a decreasing trend.

Effects of temperature and precipitation on drought trends in Xinjiang, China

The characteristics of drought in Xinjiang Uygur Autonomous Region(Xinjiang),China have changed due to changes in the spatiotemporal patterns of temperature and precipitation,however,the effects of temperature and precipitation—the two most important factors influencing drought—have not yet been thoroughly explored in this region.In this study,we first calculated the standard precipitation evapotranspiration index(SPEI)in Xinjiang from 1980 to 2020 based on the monthly precipitation and monthly average temperature.Then the spatiotemporal characteristics of temperature,precipitation,and drought in Xinjiang from 1980 to 2020 were analyzed using the Theil-Sen median trend analysis method and Mann-Kendall test.A series of SPEI-based scenario-setting experiments by combining the observed and detrended climatic factors were utilized to quantify the effects of individual climatic factor(i.e.,temperature and precipitation).The results revealed that both temperature and precipitation had experienced increasing trends at most meteorological stations in Xinjiang from 1980 to 2020,especially the spring temperature and winter precipitation.Due to the influence of temperature,trends of intensifying drought have been observed at spring,summer,autumn,and annual scales.In addition,the drought trends in southern Xinjiang were more notable than those in northern Xinjiang.From 1980 to 2020,temperature trends exacerbated drought trends,but precipitation trends alleviated drought trends in Xinjiang.Most meteorological stations in Xinjiang exhibited temperature-dominated drought trend except in winter;in winter,most stations exhibited precipitation-dominated wetting trend.The findings of this study highlight the importance of the impact of temperature on drought in Xinjiang and deepen the understanding of the factors influencing drought.

Characteristics of Precipitation and Temperature over the Past 40 Years in Zibo City

Based on monthly precipitation and temperature data of Zibo City over the years from 1966 to 2005,the spatial and temporal characteristics of precipitation and temperature in five districts and three counties of Zibo were analyzed by using climatic diagnosis methods including trend analysis and the method of Mexican-hat wavelet transform analysis. The results showed that the precipitation and temperature in Zibo experienced the interdecadal variations. The precipitation slowly increased at an average annual rate of 1.5 mm,and there existed multi-scale oscillation periods such as 32,25-29,10-23 a and quasi-5 a. Meanwhile,significant mutations were showed in 1977 and 1995. The precipitation was on the high side before 1977 and after 1995 while it was on the low side between 1977 and 1995. The yearly average temperature increased at the rate of 0.48 ℃/10 a,and there existed multi-scale oscillation periods such as 21-32,17-21,9-13 and 2-3 a. In addition,the significant mutation was showed in 1991. The temperature was colder before 1991 while after 1991,it was warmer. The results also indicated that the precipitation and temperature of Zibo City varied greatly in regional distribution,i.e.,the precipitation decreased gradually from south to north,and the temperature in the midst of Zibo City was higher than that in the south and the north,which could be divided into 3 types:south-based type,midst-based type and north-based type.

Temperature and precipitation trends in Minqin Desert during the period of 1961-2007

This paper analyzed the data of temperature and precipitation in Minqin,typical desert area in north-west China,during the period of 1961 2007 by linear regression.The result indicated that the increasing rate of the mean annual temperature in Minqin was higher than that of the average of China;and the temperature in February increased by 3.01oC averagely in the past 47 years.The climate in Minqin displayed an evident warming trend.However,there was no evidently increasing trend of precipitation in the past 47 years,and drought occurred during the whole growing season.