Characteristics of Dry and Wet Climate in Shandong Province Based on Standardized Precipitation Index

Based on the monthly precipitation data of 116 meteorological stations in Shandong Province during 1970-2021,standardized precipitation index(SPI)was calculated,and the methods of linear fitting,mutation test and Morlet wavelet analysis were used to analyze the change trend and temporal and spatial distribution characteristics of SPI index in the past 52 years.The results show that there were more normal years in Shandong Province,and the frequency reached 38.46%.There was severe drought in the 1980s and more wet years after 2003.SPI index showed an upward trend in spring,summer and winter but a weak arid trend in autumn.In addition,intense dry weather was more frequent in summer.Spatially,the climate was normal or humid in most areas of Shandong Province.The regions with more wet years were located in the central and northeast Shandong and the peninsula,while the climate was normal in the southwest and north of Shandong.The areas with more dry years were mainly located in the northwest of Shandong Province.There was mainly local and global drought in Shandong Province,and the arid area showed a decreasing trend.In the past 52 years,Shandong Province experienced quasi-4 times of alternation between dry and wet climate.The long period of 21 a was the first main period,and the climate would be still wet in Shandong Province in the future.In terms of mutation,the climate in Shandong Province became humid after 2003,and 2003 was the mutation point.After the abrupt change,the climate changed from gradually drying to wetting.

Spatio-Temporal Analysis of Drought in the North-Eastern Coastal Region of Vietnam Using the Standardized Precipitation Index (SPI)

Spatio-temporal analysis of drought provides valuable information for drought management and damage mitigation. In this study, the Standardized Precipitation Index at the time scale of 6 months (SPI-6) is selected to reflect drought conditions in the North-Eastern coastal region of Vietnam. The drought events and their characteristics from 1981 to 2019 are detected at 9 meteorological stations and 10 Chirps rainfall stations. The spatio-temporal variation of drought in the study region is analyzed on the basis of the number, duration, severity, intensity, and peak of the detected drought events at the 19 stations. The results show that from 1981 to 2019 the drought events mainly occurred with 1-season duration and moderate intensity and peak. The number, duration, severity, and peak of the drought events were the greatest in the period 2001-2010 and were the smallest in the period 2011-2019. Among the 19 stations, the drought duration tends to decrease at 11 stations, increase at 7 stations, and has a slight variant at 1 station;the drought severity tends to decrease at 14 stations, increase at 4 stations, and has not a significant trend at 1 station;the drought intensity tends to decrease at 17 stations, increase at 1 station, and has a slight variant at 1 station;and the drought peak tends to decrease at 18 stations and increase at 1 station.

Meteorological Drought Detection and Forecast Using Standardized Precipitation Index and Univariate Distribution Models: Case Study of Bamako, Mali

As an extended period of unusually dry weather conditions without sufficient rain, drought poses enormous risk on societies. Characterized by the absence of precipitation for long periods of time, often resulting in water scarcity, droughts are increasingly posing significant environmental challenges. Drought is therefore considered an important element in the management of water resources, especially groundwater resources during drought. This study therefore sought to investigate the rainfall variability and the frequency of drought for the period 1991 to 2020 in Bamako based on monthly rainfall data from Bamako-Senou gauge station. The standardized precipitation index (SPI) for 12-month, 6-month and 3-month timescales and the SPI for annual totals were used to characterized drought in the study area (Bamako). Univariate parametric probability distributions such as Normal, Log-normal, Gumbel type I and Pearson type III (P3) distributions were fitted with drought variables (severity and duration) for future planning and management. Non-parametric test such as Mann-Kendall trend test was also used to detect trend in annual rainfall data. The results showed that based on 12-month SPI, Bamako experienced two (02) extreme droughts one in July 2002 (SPI = -2.2165) and another in June 2015 (SPI = -2.0598 QUOTE SPI=-2.0598 ). Drought years represented 46.67% for the overall periods according to the SPI for annual totals. The result further indicated that based on the goodness of fit test, the P3 distribution represents the best fitted distribution to both drought severity and duration over Bamako. Bamako is expected to experience several severe severities with higher and shorter duration in the future. Severities with 1, 2, 6, and 10-month duration had return periods ranged from 2.4 to 3.8 years, while 5, 10, 20, 25, 50, and 100-year return periods had 18.51, 26.08, 33.25, 35.50, 42.38, and 49.14 severities, respectively, and durations associated to these severities were 19.8, 26.9, 33.5, 35.6, 42, and 48.2 months, respectively.

Spatial and Temporal Characteristics of Drought and Flood in Quanzhou Based on Standardized Precipitation Index (SPI) in Recent 55 Years

To analyze the characteristics of drought and flood variations in Quanzhou during recent 55 years, the standardized precipitation index (SPI) and Empirical Orthogonal Function (EOF) and Rotated Empirical Orthogonal Function (REOF) were calculated by using the monthly precipitation data from 6 meteorological bureaus across Quanzhou for 1960-2014. Results showed that: 1) During 1960-2014, the drought and flood showed Periodic variation characteristics in Quanzhou, the specific period of frequent drought was 1963-1972, 1977-1986 and 2009-2011, and the specific period of frequent flood was 1961-1962, 1972-1975, 1990-1992 and 1997-2007;the drought and flood did not have significant tendency of variation in Spring and Summer, and the drought and flood showed a non-significant downward trend in Autumn and Winter. 2) The drought and flood variation had relatively consistent trend in Quanzhou, but there was a big difference on the northwest mountainous area, the middle semi-mountainous area and the southeast coast area in some periods. 3) The precipitation cell and distribution in every season were Nan’an and Anxi, but there was a big difference in rainfall less area: it was Yongchun and Dehua in Spring, Chongwu and Jinjiang in Summer, Chongwu in Autumn, Dehua and Chongwu in Winter.

Spatiotemporal analysis of drought variability based on the standardized precipitation evapotranspiration index in the Koshi River Basin, Nepal

Drought is an inevitable condition with negative impacts in the agricultural and climatic sectors,especially in developing countries.This study attempts to examine the spatial and temporal characteristics of drought and its trends in the Koshi River Basin(KRB)in Nepal,using the standardized precipitation evapotranspiration index(SPEI)over the period from 1987 to 2017.The Mann-Kendall test was used to explore the trends of the SPEI values.The study illustrated the increasing annual and seasonal drought trends in the KRB over the study period.Spatially,the hill region of the KRB showed substantial increasing drought trends at the annual and seasonal scales,especially in summer and winter.The mountain region also showed a significant increasing drought trend in winter.The drought characteristic analysis indicated that the maximum duration,intensity,and severity of drought events were observed in the KRB after 2000.The Terai region presented the highest drought frequency and intensity,while the hill region presented the longest maximum drought duration.Moreover,the spatial extent of drought showed a significant increasing trend in the hill region at the monthly(drought station proportion of 7.6%/10 a in August),seasonal(drought station proportion of 7.2%/10 a in summer),and annual(drought station proportion of 6.7%/10 a)scales.The findings of this study can assist local governments,planners,and project implementers in understanding drought and developing appropriate mitigation strategies to cope with its impacts.

Drought trend analysis in a semi-arid area of Iraq based on Normalized Difference Vegetation Index, Normalized Difference Water Index and Standardized Precipitation Index

Drought was a severe recurring phenomenon in Iraq over the past two decades due to climate change despite the fact that Iraq has been one of the most water-rich countries in the Middle East in the past.The Iraqi Kurdistan Region(IKR)is located in the north of Iraq,which has also suffered from extreme drought.In this study,the drought severity status in Sulaimaniyah Province,one of four provinces of the IKR,was investigated for the years from 1998 to 2017.Thus,Landsat time series dataset,including 40 images,were downloaded and used in this study.The Normalized Difference Vegetation Index(NDVI)and the Normalized Difference Water Index(NDWI)were utilized as spectral-based drought indices and the Standardized Precipitation Index(SPI)was employed as a meteorological-based drought index,to assess the drought severity and analyse the changes of vegetative cover and water bodies.The study area experienced precipitation deficiency and severe drought in 1999,2000,2008,2009,and 2012.Study findings also revealed a drop in the vegetative cover by 33.3%in the year 2000.Furthermore,the most significant shrinkage in water bodies was observed in the Lake Darbandikhan(LDK),which lost 40.5%of its total surface area in 2009.The statistical analyses revealed that precipitation was significantly positively correlated with the SPI and the surface area of the LDK(correlation coefficients of 0.92 and 0.72,respectively).The relationship between SPI and NDVI-based vegetation cover was positive but not significant.Low precipitation did not always correspond to vegetative drought;the delay of the effect of precipitation on NDVI was one year.

Drought and flood characteristics in the farmingpastoral ecotone of northern China based on the Standardized Precipitation Index

The farming-pastoral ecotone of northern China(FPENC)provides an important ecological barrier which restrains the invasion of desert into Northwest China.Studying drought and flood characteristics in the FPENC can provide scientific support and practical basis for the protection of the FPENC.Based on monthly precipitation data from 115 meteorological stations,we determined the changes in climate and the temporal and spatial variations of drought and flood occurrence in the FPENC during 1960-2020 using the Standardized Precipitation Index(SPI),Morlet wavelet transform,and inverse distance weighted interpolation method.Annual precipitation in the FPENC showed a slightly increasing trend from 1960 to 2020,with an increasing rate of about 1.15 mm/a.The interannual SPI exhibited obvious fluctuations,showing an overall non-significant upward trend(increasing rate of 0.02/a).Therefore,the study area showed a wetting trend in recent years.Drought and flood disasters mainly occurred on an interannual change cycle of 2-6 and 9-17 a,respectively.In the future,a tendency towards drought can be expected in the FPENC.The temporal and spatial distribution of drought and flood differed in the northwestern,northern,and northeastern segments of the FPENC,and most of the drought and flood disasters occurred in local areas.Severe and extreme drought disasters were concentrated in the northwestern and northeastern segments,and severe and extreme flood disasters were mainly in the northeastern segment.Drought was most frequent in the northwestern segment,the central part of the northeastern segment,and the northern part of the northern segment.Flood was most frequent in the western part of the northwestern segment,the eastern part of the northeastern segment,and the eastern and western parts of the northern segment.The accurate evaluation of the degrees of drought and flood disasters in the FPENC will provide scientific basis for the regional climate study and critical information on which to base decisions regarding environmental protection and socio-economic development in this region.

Characteristics of Drought and Humidification Based on Standardized Precipitation Index in Weifang City during the Past 50 Years

[Objective] This study aimed to analyze the evolution characteristics and occurrence patterns of droughts and floods in Weifang City. [Method] Based on the monthly precipitation data during 1961-2010 obtained from nine meteorological sta- tions of Weifang City, by using standardized precipitation index, monthly SPI index of Weifang City during the past 50 years was calculated to analyze the spatial and temporal distribution characteristics of drought and humidification in Weifang City. [Result] The results showed that the variation of drought and humidification had stage characteristics in Weifang City, which was relatively humid in the 1960s and 1970s and developed from extremely humid in early 1960s to dry in late 1970s, persistent drought was observed throughout the range of Weifang City in the 1980s, and the variation tended to be smooth during the 1990s-2000s. Spatial distribution of drought and humidification in Weifang City showed certain regional characteristics. In the 1960s, the mid-west region of Weifang City was relatively humid, while the southeastern region was relatively dry; in the 1970s, there was little difference among the drought and humidification extent in each region; in the 1980s, each region of Weifang City was generally dry, specifically, drought in the southeastern region was the most severe, while drought in the northern region was the slightest; in the 1990s and 2000s, variation of drought and humidification in each region of Weifang City was basically the same. The uneven spatial and temporal distribution of precipi- tation led to abnormal distribution of drought and humidification in some areas, such as the abnormal phenomenon in 1999; the spatial distribution of drought and humidi- fication duration in each generation had their own characteristics, which brought diffi- culties to the unified deployment of drought and flood control departments. [Conclu- sion] This study provided theoretical basis for the drought resistance, waterlogging prevention and disaster reduction in Weifang City under the background of climate change.

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.

基于SPI-RRV指数中国气象干旱及其风险时空演变特征研究

为全面揭示变化环境下我国多维气象干旱特征,耦合气象干旱指数(SPI)和可靠性-回弹性-脆弱性(RRV)指数,提出了一种基于SPI-RRV指数的干旱风险评价方法,定量评价了中国气象干旱及其风险的时空演变特征。结果表明:SPI-RRV指数具有特征稳定和时空可比性强的特点,能够较为准确地评估气象干旱风险时空演变特征;南方平均干旱栅格比、干旱月占比和频次大于北方,湿润区和半湿润区干旱历时短、烈度大,半干旱区和干旱区干旱历时长、烈度相对较小;干旱高风险区转移具有显著年代际变化规律,空间上从西北向西南地区转移。

基于标准化降水指数(SPI)的宁夏中部干旱带旱灾危险性时空演变特征

[目的]揭示宁夏中部干旱带旱灾危险性的时空特征,为宁夏中部干旱带农业生产、农业灾害防治、种植结构调整和农业灌溉指导提供科学依据。[方法]收集宁夏中部干旱带的沙坡头区、中宁县、同心县、盐池县、海原县5个气象站点的气象观测资料,采用标准化降水指数(SPI)分析了近39年(1981—2019年)干旱等级的时空变化,并结合GIS技术评价其旱灾危险性时空演变特征。[结果]SPI 12结果表明代际干旱趋势呈波动中加剧趋势(趋势线斜率范围为-0.004~0.003)。SPI 3结果表明季尺度旱灾危险性时空分布异质性明显,空间上呈现出南低北高的特征,而时间上则表现为连旱特征突出。春冬两季旱灾发生频率高于45%;夏、秋两季干旱现象不显著,干旱发生频率处于10.26%~43.59%之间;旱灾危险性时空演变特征评价结果表明代际旱灾危险性呈现先下降后上升的变化趋势。季尺度旱灾危险性时空差异明显,空间上表现为旱灾危险性由南向北升高,时间上表现为春冬两季旱灾危险性较高,而夏、秋两季旱灾危险性较低。[结论]宁夏中部干旱带季尺度旱灾危险性时空异质性明显,沙坡头区、中宁县旱灾危险性高,未来应加强春、秋、冬三季的旱灾防治。

基于SPI的福建省干湿特征与ENSO的关联性分析

根据福建省17个气象站点1970—2019年的逐月降水数据,计算了不同时间尺度的标准化降水指数(Standardized Precipitation Index,SPI),并利用Mann-Kenddall检验、相关性分析等方法,分析了福建省干湿时空变化特征,及其与El Ni1o-Southern Oscillation(ENSO)事件的关联性。结果表明:近50年来,福建省以正常为主,轻旱与轻湿次之,发生频次最少的是特旱与特湿。年尺度上,福建省整体呈湿润化趋势,但季节变化差异较大,其中,春季呈明显的干旱趋势,夏季呈较为明显的湿润趋势,秋、冬季变化趋势不显著。福建省沿海及闽北山区易出现旱涝极值,中间地带干湿分布以轻级、中级和正常为主。ENSO事件的强度与SPI的变化呈正相关,ENSO冷暖事件对降水的影响具有滞后性,ENSO冷事件对福建省SPI影响的滞后时间为5个月,ENSO暖事件的滞后时间为0~5个月。

基于SPI的1961—2020年昌吉地区作物生长季气象干旱时空特征研究

基于昌吉地区1961—2020年的气象资料分析作物生长季标准化降水指数(SPI-7)的年际和年代际变化特征,揭示作物生长季干旱发生频率和强度。结果表明:1961—2020年昌吉地区作物生长季水分呈增加趋势,标准化降水指数以0.08/10 a的速率增加。气象干旱呈干—湿—干的年代际变化趋势,其中在1981年发生突变。干旱强度呈增加趋势,干旱发生面积呈弱减少趋势。东部地区是干旱高发区,但以轻旱为主;西部地区则是中旱、重旱和特旱高发区。昌吉地区的气象干旱存在6、9、16 a的周期震荡,与历史灾情具有很好的吻合性。

基于SPI指数的漳州市季节性旱涝特征分析

文章利用漳州市10个国家级气象观测站近30年逐月降水资料,采用标准化降水指数(SPI)和相关分析的方法对漳州市旱涝特征进行分析。研究结果表明:春季整体有偏旱趋势,其中1990s和2010s偏涝,2000s和2020s前期偏旱;夏季整体往偏旱发展,其中1990s和2000s偏涝,2010s和2020s前期夏季偏旱;秋季往偏涝趋势发展,1990s秋季和2020s前期偏旱,2010s偏涝;冬季整体有偏旱的趋势,其中1990s秋季偏涝,2000s和2020s前期冬季偏旱。

Drought characteristics of Henan province in 1961-2013 based on Standardized Precipitation Evapotranspiration Index

Drought is one of the most complex natural hazards affecting agriculture, water resources, natural ecosystems, and society. The negative societal consequences of drought include severe economic losses, famine, epidemics, and land degradation. However, few studies have analyzed the complexity of drought characteristics, both at multiple time scales and with variations in evapotranspiration. In this study, drought occurrences were quantified using a new drought index, the Standardized Precipitation Evapotranspiration Index （SPEI）, based on observed data of monthly mean temperature and precipitation from 1961 to 2013 in Henan province, central China. Based on the SPEI values of each weather station in the study the frequency and severity of meteorological droughts were computed, and the monthly, seasonal, and annual drought frequency and intensity over a 53-year period were analyzed. The spatial and temporal evolution, intensity, and the primary causes of drought occurrence in Henan were revealed. The results showed that the SPEI values effectively reflected the spa- tial and temporal pattern of drought occurrence. As the time scale decreased, the amplitude of the SPEI increased and droughts became more frequent. Since 1961, drought has oc- curred at the annual, seasonal, and monthly scales, and the occurrence of drought has in- creased. However, regional distribution has been uneven. The highest drought frequency, 35%, was observed in the Zhoukou region, while the lowest value, -26%, was measured in central and western Henan. The most severe droughts occurred in the spring and summer, followed by autumn. Annually, wide-ranging droughts occurred in 1966-1968, 1998-2000, and 2011-2013. The drought intensity showed higher values in north and west Henan, and lower values in its east and south. The maximum drought intensity value was recorded in Anyang, and the minimum occurred in Zhumadian, at 22.18% and 16.60%, respectively. The factors with the greatest influence on drought occurrence are increasing temperatures, the Eurasian atmospheric circulation patterns, and the El Nino effect.

利用短序列区域站资料计算干旱指数SPI的应用研究

干旱是全球影响范围最广、危害最重的自然灾害之一。标准化降水指数(SPI)是干旱监测业务和科研中使用最为广泛的气象干旱指数之一。目前,中国已建设了大量高密度的区域自动气象观测站,这些站由于缺乏长历史序列数据,无法用于计算SPI,如何利用这些短时间序列区域站数据开展精细化干旱监测评估是目前关注的重点。利用1960-2020年2032个国家气象站和2010-2020年云南省1009个区域站日降水数据,选取31个国家站作为方法试验站,构建了通过伽马分布参数插值法来拟合区域站的SPI(Iab),并与常用的邻站替代法、多元线性回归法进行了对比,进行交叉检验和误差分析。通过对比拟合值与真值的相关系数、均方根误差和平均绝对误差得出,除在中国西北站点稀疏的地区外,拟合值Iab均明显优于其他两种方法的拟合结果。在不同季节和不同时间尺度下,参数插值法拟合得到的SPI(Iab)效果最好,特别是在中国中东部地区的Iab值较其他方法平均误差减小0.02~0.30;北京、昆明历年拟合值Iab与真值Iz误差变幅最大为0.16,不到半个干旱等级0.25;拟合值Iab与真值Iz的相关系数达0.999,通过0.001的显著性检验。采用该方法进行区域站干旱过程的监测结果显示,利用高密度区域站计算的干旱指数SPI比仅利用国家站插值得到的SPI更接近干旱灾害实况。总体而言,伽马分布参数插值法可以用于高精度短序列区域站降水资料推算干旱指数SPI,从而实现气象干旱精密监测、预报和评估服务。

基于SPI的1979—2020年广东气象干旱的时空特征

基于1979—2020年的月降水数据计算标准化降水指数(SPI),分析了广东省近42年不同尺度的干旱时间和空间特征,结果发现:(1)1979—2020年广东省有略湿润趋势;SPI10年干旱倾向为“三明治”状分布,珠三角和粤北地区逐渐湿润化,粤东和粤西呈略干旱化。(2)广东省年际SPI分布主要有6种表现类型:模态1反映南涝北旱或北涝南旱2种类型;模态2反映东旱西涝或西旱东涝2种类型;模态3反映沿海涝内陆旱或沿海旱内陆涝2种类型。(3)基于季节尺度:春季的干旱化趋势最为明显,夏季非干旱化趋势明显;秋季是广东地区干旱的高发时期,干旱分布最广;春季发生轻旱以上等级的地区主要位于雷州半岛一带;秋冬连旱在广东普遍发生。

基于SPI的云南省多尺度干旱时空演变特征识别

【目的】识别云南省多尺度干旱的时空演变特征。【方法】基于云南省36个气象站31 a的气象数据,基于标准化降水指数(SPI),结合GIS空间分析、非参数Mann-kendall趋势检验,识别云南省多尺度气象干旱时空分布及演变特征。【结果】(1)SPI在年尺度、季节尺度均呈波动变化趋势,除春季SPI略有增长外,夏季、秋季、冬季和年尺度的SPI均表现为减小趋势,秋季SPI变幅最大,冬季变幅最小。(2)年尺度干旱频率分布在32.26%~50.00%之间,主导的干旱等级为轻微干旱和极端干旱,干旱频率高值区主要分布在文山、红河、昆明、楚雄、德宏。(3)春、夏、秋、冬4个季节的干旱频率分别为39.86%、39.83%、38.43%、41.33%,尽管季节间干旱频率差异较小,但不同季节主导性干旱等级差异较大。除春季外,各季节的主导性干旱等级均包含极端干旱。(4)年尺度上,除5个站点干旱呈增强趋势外,其余站点均无显著变化趋势;春季大部分站点干旱演变呈减小趋势,而夏季、秋季、冬季则分别有11、6、2个站点呈显著增强趋势。【结论】云南省年尺度和季节尺度干旱频率分布及演变趋势呈明显的时空分异特征,区域干旱以季节性干旱为主,其中春旱、冬旱的干旱频率和等级总体较高。

基于SPI的金沙江下游气象干旱时空分布特征及预测方法

基于金沙江下游地区30个气象观测站1960~2020年逐月降水数据,选用标准化降水指数(SPI)作为气象干旱指标,分析了该流域干旱在3个月和12个月时间尺度上的时空演变特征,并分别构建了流域南、北部旱涝的均生函数预测模型。结果表明:金沙江下游干旱主要表现为全域一致型和南北反相型两种模态。在3个月时间尺度上,干旱频次较高,范围较广,以轻旱为主;在12个月时间尺度上,干旱频次大幅降低,流域北部中旱及重旱的比例增加。年度干旱强度和范围均呈增加趋势。季节干旱强度除冬季为减弱趋势外,其他季节均呈增强趋势;秋季干旱范围表现为增加趋势,春季和冬季表现为减小趋势,夏季变化不明显。夏季干旱发生频次最高,且对年度干旱影响最大。均生函数预测模型可以较好地模拟和预测金沙江下游旱涝变化趋势,流域南部模拟效果优于北部,对极值的模拟效果更佳。

基于SPI指数的云南省干旱时空特征分析

干旱是云南省主要的自然灾害之一,为全面了解云南省气象干旱的时空演变特征,基于云南省104个气象站点1959~2018年逐月降雨量资料,计算标准化降水指数SPI,分析云南省干旱的时空变化特征。结果表明:(1)云南省不同尺度的SPI值随时间尺度的增加,波动逐渐减小,且呈现出一定的周期性变化特征。(2)近60 a以来,云南省每年都会有地区发生干旱,大部分以轻旱、中旱为主,但重旱、特旱发生的比例也在增加;干旱强度和范围均呈缓慢上升趋势,且干旱的范围越大,干旱强度越强。(3)夏、秋季节干旱强度与干旱范围均呈上升趋势,春、冬季节呈下降趋势。(4)近年来,滇东南、滇西南地区成为云南省干旱的高发区。