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Drought is one of the most destructive types of natural disasters, causing great losses of every aspects worldwide. Using a three‐dimensional (longitude, latitude, and time) clustering method based on gridded 3 month standardized precipitation evapotranspiration index data with a resolution of 0.25° collected for East China between 1960 and 2017, we identified and analysed five characteristics of drought events via the Mann–Kendall (MK) test. The results revealed that this method could capture drought events on the basis of their spatiotemporal characteristics. Drought development processes could be visualized via the spatial expansion of drought patches and the transferring path (reconstructed from the centroids of drought patches observed each month). By applying this identification method to the territory of East China, the occurrence of 174 droughts in the last six decades could be determined; furthermore, their objective existence in the spatiotemporal scale was confirmed by comparing the results with historical records and soil moisture data. The increasing moving speed of the centroids and the non‐repetitive rate of the impacted areas suggests that an increasing number of regions have likely been affected over time by large‐scale drought events. The drought patches associated with all of the events identified in the present study tended to move westward in South China and eastward in southwestern China. The remaining four characteristics (i.e., duration, severity, affected area, and intensity), were used to quantify the degree of drought, along with its development, where significant decreasing trends were found among the first three characteristics. In southwestern China, drought events decreased in frequency, but increased spatially, whereas drought events in southeastern China showed an opposite change. Drought events with a small spatial scale occurred more frequently in coastal regions. The majority of drought events mainly occurred in central and North China and moved northward. [ABSTRACT FROM AUTHOR]

Crop reference evapotranspiration (ET0), which connects the energy and water balance, is an important indicator used in water resource management and agricultural production. On the basis of daily meteorological data from 479 observation stations, we investigate changes in ET0 and associated climate factors across the main grain‐producing area (MGPA) of China from 1960 to 2015. The Mann–Kendall test and Sen's slope estimator were applied to detect trends in ET0, and regression analyses and composite analyses were used to evaluate the contributions of climatic variables and large‐scale anomalies that may affect ET0. The results of this study show that ET0 in the MGPA decreased (−2.67 mm/decade) during summer throughout the past 56 years, and that this change is largely attributable to decreased sunshine duration and wind speed (WS). Furthermore, decreased WSs in the 850‐hpa geostrophic wind field, are responsible for decreases in ET0 in Northeast China Region (−1.85 mm/decade), which affect ET0 by significantly weakening the observed surface WS. Meanwhile, significant low cloud cover variations accounted for the decrease in ET0 in the Huang‐Huai‐Hai Region (−7.85 mm/decade), Loess Plateau Region (−2.91 mm/decade), Yangtze River Region (−3.96 mm/decade), and Southwest China Region (−2.71 mm/decade). However, decreases in the integrated atmospheric water vapour content (IWVC), which act to weaken the surface relative humidity, are hypothesised to increase ET0 in the South China Region (1.25 mm/decade). Topographic map of China with 479 meteorological stations across main grain‐producing area (MGPA). [ABSTRACT FROM AUTHOR]

ABSTRACT This research analyses the long-term changes in the precipitation structure over the karst area of southwest China, as recorded by 153 national meteorological stations from 1959 to 2009. Study results are as follows: (1) The karst area of southwest China is categorized into six similar precipitation clusters, including two low-rainfall clusters located in the western and northern areas and four high-rainfall clusters distributed in the eastern and southern areas. (2) Although the decreasing trend of annual total precipitation is weak, autumn precipitation decreases significantly over the whole study area. The autumn total precipitation decreases significantly at 51% of the stations because the autumn wind and water vapor flux of the study area gradually decreased, and the autumn low-latitude and mid-latitude sea surface temperature ( SST) of East Asia continues to rise and gradually leads to positive sea anomalies. (3) The number of rainy days decreases at 85.6% of the stations, especially in the central and southeastern regions of the area. Consequently, almost 53% of the total stations are characterized by an increasing precipitation intensity. (4) The occurrence time of the accumulated percentage precipitation in the western mountain areas is usually later than that in the eastern coastal areas, and the occurrence date of accumulated percentage precipitation ( DAP) seems to occur increasingly earlier over the whole study area. (5) Light rain occurs more frequently (76% of annual total rainy days) and contributes 25% to annual total precipitation, whereas although heavy rains such as storms occur less frequently at 3% of annual total rainy days, it contributes almost 19% to annual total precipitation. (6) The occurrence and contribution of wet periods ( WPs) decrease with an increase in their duration. WPs with short durations (e.g. 1-4 days) tend to be the predominant precipitation events. [ABSTRACT FROM AUTHOR]