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BACKGROUND: Drought affects the characteristics of water use during crop production and so quantitatively evaluating the impacts is important. However, it remains unclear how crop water use responds to drought. To address this gap, water footprint (WF) and standardized precipitation evapotranspiration index (SPEI) were calculated by remote sensing approaches to assess the effects of drought on crop water use. Rainfed maize is the most important crop in Jilin Province, and its growth and water use are more susceptible to drought. The present study explored not only the impact of growing season drought on the maize WF values in Jilin Province, but also the response of WF values to drought at different time scales. RESULTS: Spatially, 72.94% of the WFblue pixels showed a non‐significant increase, and the WFgreen in 68% pixels decreased significantly, being mainly concentrated in the middle region. Furthermore, the pixels affected by monthly time scale drought were mainly in the middle region, whereas the pixels affected by annual time scale drought were mainly in the western region. CONCLUSION: Drought not only affected on the source and structure of agricultural water consumption, but also had different effects on WF values at different time scale. These effects had obvious spatial differences. The present study systematically explored the effects of drought on the WF values for rainfed maize in different climate regions and a consideration of these effects could provide valuable information on rainfed maize growth and the agricultural water use response to a changing climate. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Rice is a special crop, and its production differs from that of other crops because it requires a thin layer of water coverage for a long period. The calculation of the water footprint of rice production should differ from that of other crops owing to the rice growing process. This study improved the calculation of blue and grey water footprints of rice production and analyzed the variations in the water footprints for rice production under different rainfall years in Jilin Province. RESULTS: In the drought year, the green water footprint was the lowest and the blue water footprint was the highest among the three years, while in the humid year, the green water footprint was the highest and the blue water footprint was not the lowest. The areas with higher water footprints were found in the east and west regions of Jilin Province, while the areas with lower water footprints were found in the middle east and middle regions of Jilin Province. CONCLUSION: Blue water was the primary water resource for rice production, although more precipitation provided the highest green water in the humid year; also, the spatial distributions of water footprints were not the same under different rainfall years. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

ABSTRACT: Using the daily precipitation records during 1961–2013 from 686 meteorological stations across China and the atmospheric circulation indexes, this study investigates the spatio‐temporal changes in the occurrence time and length of the extreme precipitation period (EPP), as well as their influencing factors. The results show the following aspects: (1) In the last 53 years, the start dates of the extreme precipitation period (EPPS) generally advanced. The end dates of the extreme precipitation period (EPPE) are delayed, which show an increasing trend. The lengths of the extreme precipitation period (EPPL) in most of the China meteorological stations increased. (2) The spatial patterns of the trends in the occurrence time and length of the extreme precipitation period are similar and show obvious clustering. The occurrence time and length of the extreme precipitation period have obvious spatial gradient differences in their average values. In southeastern China, the average EPPS is earlier, EPPE is later than those in other regions, and their EPPL is prolonged. The EPP in northeastern China begins later and ends earlier, and its EPPL is shorter than that in other regions. (3) The western Pacific subtropical high, Northern Hemisphere polar vortex, Antarctic Oscillation, and western Pacific warm pool have significant effects on the occurrence time and length of EPP over China, and different regions show different effects. [ABSTRACT FROM AUTHOR]

ABSTRACT On the basis of the daily minimum temperature, records of 109 meteorological stations over Northeastern China ( NEC) from 1961 to 2013 and the output data of eight models from CMIP5, this study investigates the recent and future spatiotemporal changes of the frost-free season. The results show that the date of last spring frost ( LSFD) has a significant decreasing trend. Stations exhibiting significant negative trends are mostly distributed in the eastern Jilin Province and the Midwest of Heilongjiang Province. The date of first fall frost ( FFFD) and length of frost-free season ( LFFS) both show significant increasing trends. The spatial patterns of stations showing significant positive trends in the FFFD and LFFS are similar, which are mainly located in the middle part of Eastern Inner Mongolia and the south and middle parts of Changbai Mountains. The LFFSs have significant increasing trends with the magnitudes of 0.49 days/decade for RCP2.6, 1.62 days/decade for RCP4.5, and 3.85 days/decade for RCP8.5 during 2006-2100. The southern Liaoning Province and the northwestern NEC will experience the longer LFFS under each scenario between 2071 and 2100. The frost-free season indices have significant correlations with the Northern Hemisphere Polar Vortex Area index. The atmospheric circulation patterns of an anticyclonic circulation anomaly prevailed over the Lake Baikal region and a cyclonic circulation anomaly located in the northwest Pacific Ocean in springs and an anticyclonic circulation anomaly prevailed over the south part of the Russian Far East in falls block more cold air flowing into NEC, which result in the earlier LSFD and later FFFD. The adverse patterns in springs and in falls could bring out the later LSFD and earlier LSFD, respectively. Our results could benefit the prevention and reduction of frost disaster and provide a reference for the policy-making of future crop production. [ABSTRACT FROM AUTHOR]

ABSTRACT On the basis of the daily precipitation records of 442 meteorological stations throughout Northeast Asia ( NEA) from 1961 to 2009, this study investigates spatiotemporal changes in summer extreme precipitation ( SEP) and the relationship between SEP and East Asia summer monsoon ( EASM) in NEA. The results show that the spatial patterns of the trends in SEP indices are similar, with obvious clustering, except for the consecutive dry days ( CDD) index. Stations exhibiting increasing trends are mainly located in Eastern China ( EC) and the western part of Western Japan ( WJ). Stations with decreasing trends are mostly distributed in Northern China ( NC) and the southern region of Eastern Japan ( EJ). The spatial patterns of the correlations between the EASM index EASMI and the SEP indices are similar, except for the CDD index. Stations that show decreasing trends mostly exhibit positive correlations between SEP indices and the EASMI, and vice versa. The spatial patterns of trends (increasing trends in EC, decreasing trends in NC and Northeast China) in SEP indices between 1961 and 2009 have a correlation with a weakening EASM. This study demonstrates that the mechanism dominating the mean state change of the EASM also applies to SEP. A strong mid-latitude cyclone could result in a regional SEP (R99p occurred in more than 20 stations over a subregion in 1 day) in EC and Japan in weak EASM years, and could result in a regional SEP in NC in strong EASM years. [ABSTRACT FROM AUTHOR]

Interday temperature fluctuations (ITFs) have a series of direct and visible impacts on human productivity, daily life, and some rapidly occurring processes in the Earth's critical zones. The Loess Plateau of China (LPC) is characterized by Chinese continental monsoon climate and fragile ecological environment, and thus, is sensitive to ITFs. To evaluate the spatiotemporal distribution of the ITF frequency and level, and the related large‐scale circulation background, we collected daily temperature data from 53 meteorological stations in the LPC for 1961–2015, and calculated the number of days per year in which the average ITF was greater than 1°C (ITFD) and the corresponding variance of the ITF (ITFL). The annual average ITFs were mostly warming; the first half of the year experienced mainly warming, while the second half underwent cooling. The level and frequency of the interday maximum temperature fluctuation contributed greatly to increases in the interday mean temperature fluctuation level and frequency. The spatial distributions of ITFD and ITFL were related to their latitude and longitude. Stations with positive ITFD indicator trends were mostly concentrated in the southwestern LPC, while stations with negative ITFL indicator trends mainly occurred in the northwestern LPC. At an 850 hPa geopotential height, the stronger ITFs in spring more strongly correlated with the Mongolian high and Aleutian low. While at a 500 hPa geopotential height, the ITF were more strongly correlated with the Mongolian high. These results suggest that ITFs are more complex than previously reported and may need to be considered in future climate change assessments. [ABSTRACT FROM AUTHOR]

BACKGROUND Field-scale changes in the water footprint during crop growth play an important role in formulating sustainable water utilisation strategies. This study aimed to explore field-scale variation in the water footprint of growing sunflowers in the western Jilin Province, China, during a 3-year field experiment. The goals of this study were to (1) determine the components of the 'blue' and 'green' water footprints for sunflowers sown with water, and (2) analyse variations in water footprints and soil water balance under different combinations of temperature and precipitation. Specific actions could be adopted to maintain sustainable agricultural water utilisation in the semi-arid region based on this study. RESULTS The green, blue, and grey water footprints accounted for 93.7-94.7%, 0.4-0.5%, and 4.9-5.8%, respectively, of the water footprint of growing sunflowers. The green water footprint for effective precipitation during the growing season accounted for 58.8% in a normal drought year but 48.2% in an extreme drought year. When the effective precipitation during the growing season could not meet the green water use, a moisture deficit arose. This increase in the moisture deficit can have a significant impact on soil water balance. CONCLUSION Green water was the primary water source for sunflower growth in the study area, where a scarcity of irrigation water during sunflower growth damaged the soil water balance, particularly in years with continuous drought. The combination of temperature and precipitation effected the growing environment, leading to differences in yield and water footprint. The field experiments in this area may benefit from further water footprint studies at the global, national and regional scale. © 2016 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Water footprint ( WF) methodology is essential for quantifying total water consumption of crop production and making efficient water management policies. This study calculated the green, blue, grey and total WFs of maize production in Northeast China from 1998 to 2012 and compared the values of the provinces. This study also analyzed the spatial variation and structure characteristics of the WFs at the prefecture level. RESULTS The annual average WF of maize production was 1029 m3 per ton, which was 51% green, 21% blue and 28% grey. The WF of maize production was highest in Liaoning Province, moderate in Heilongjiang Province and lowest in Jilin Province. The spatial differences of the WFs calculated for the 36 major maize production prefectures were significant in Northeast China. There was a moderate positive spatial autocorrelation among prefectures that had similar WFs. Local indicator of spatial autocorrelation index ( LISA) analysis identified prefectures with higher WFs in the southeast region of Liaoning Province and the southwest region of Heilongjiang Province and prefectures with lower WFs in the middle of Jilin Province. CONCLUSION Spatial differences in the WF of maize production were caused mainly by variations in climate conditions, soil quality, irrigation facilities and maize yield. The spatial distribution of WFs can help provide a scientific basis for optimizing maize production distribution and then formulate strategies to reduce the WF of maize production. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]