Multi-scale assessments of droughts: A case study in Xinjiang, China.

Understanding the multi-scale variation of drought is essentially important in drought assessment. Now, a comprehensive assessment is still lacking on the meteorological, ecological and hydrological drought perspectives. In order to better investigate multi-scale droughts, we carried out a comprehensive analysis of their long-term variation based on the two drought indices and observation data in Xinjiang, China, from 1961 to 2015. The two indices are the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI). The results show that the SPI and SPEI are highly consistent for most stations and time scales in Xinjiang. Based on multi-scale and considered evaporative demand, the SPEI from 1961 to 2015 showed a wetting trend followed by a drying trend (as of 1997), giving an overall slight drying trend (-0.0122±0.0043 per year) for the 54-year period. We assessed the sensitivity of the two drought indices to precipitation (P) and potential evapotranspiration (PET) and found that the SPEI shows different sensitivity to P and PET. In arid regions characterized by high PET, drought severity is mostly determined by changes in PET. The intensified warming and diminished precipitation in Xinjiang that have been observed over the past two decades have resulted in SPEI-drought severity. These changes also amplify the risk of ecological drought. However, the hydrological drought was highly complex and not entirely comparable to the SPEI and SPI droughts. Hydrological records indicate that runoff in most rivers in the Tianshan Mountains has increased, whereas runoff in the Kunlun Mountains is either stable or has slightly decreased over the past 20years. A moderately high and statistically significant correlation between the runoff anomaly and the SPEI and SPI was revealed for four major rivers in the region. This implies that the accelerated river runoff in Xinjiang is a function of both precipitation and increasing glacier melt.

[1]  S. Malyshev,et al.  Snowfall less sensitive to warming in Karakoram than in Himalayas due to a unique seasonal cycle , 2014 .

[2]  Yang Liu,et al.  Response of vegetation NDVI to climatic extremes in the arid region of Central Asia: a case study in Xinjiang, China , 2018, Theoretical and Applied Climatology.

[3]  Sergio M. Vicente-Serrano,et al.  A New Global 0.5° Gridded Dataset (1901–2006) of a Multiscalar Drought Index: Comparison with Current Drought Index Datasets Based on the Palmer Drought Severity Index , 2010 .

[4]  L. Pereira,et al.  Analysis of SPI drought class transitions using loglinear models , 2006 .

[5]  E. Hovmöller,et al.  The Trough-and-Ridge diagram , 1949 .

[6]  T. Mavromatis.  Drought index evaluation for assessing future wheat production in Greece , 2007 .

[7]  B. Abiodun,et al.  Potential impacts of afforestation on climate change and extreme events in Nigeria , 2013, Climate Dynamics.

[8]  R. Trigo,et al.  Evidence of increasing drought severity caused by temperature rise in southern Europe , 2014 .

[9]  H.A.J. van Lanen,et al.  Making the distinction between water scarcity and drought using an observation‐modeling framework , 2013 .

[10]  Yaning Chen,et al.  Potential impacts of climate change on vegetation dynamics in Central Asia , 2015 .

[11]  T. Bolch,et al.  Substantial glacier mass loss in the Tien Shan over the past 50 years , 2015 .

[12]  Luis S. Pereira,et al.  Climate trends and behaviour of drought indices based on precipitation and evapotranspiration in Portugal , 2012 .

[13]  H. B. Mann.  Nonparametric Tests Against Trend , 1945 .

[14]  Liang Zhong-qin.  Ponder on the issues of water resources in the arid region of northwest China , 2012 .

[15]  Zhi Li,et al.  Multivariate assessment and attribution of droughts in Central Asia , 2017, Scientific Reports.

[16]  T. Jiang,et al.  Spatial Variation and Trends in PDSI and SPI Indices and Their Relation to Streamflow in 10 Large Regions of China , 2010 .

[17]  Sergio M. Vicente-Serrano,et al.  A Multiscalar Global Drought Dataset: The SPEIbase: A New Gridded Product for the Analysis of Drought Variability and Impacts , 2010 .

[18]  Mark A. Davis,et al.  Experimental support for a resource-based mechanistic model of invasibility , 2001 .

[19]  X. Gou,et al.  Tree-ring-based moisture variability in western Tianshan Mountains since A.D. 1882 and its possible driving mechanism , 2016 .

[20]  S. Vicente‐Serrano,et al.  Standardized precipitation evapotranspiration index (SPEI) revisited: parameter fitting, evapotranspiration models, tools, datasets and drought monitoring , 2014 .

[21]  Zhi Li,et al.  Progress and prospects of climate change impacts on hydrology in the arid region of northwest China. , 2015, Environmental Research.

[22]  Ken Takahashi,et al.  Dry and wet rainy seasons in the Mantaro river basin (Central Peruvian Andes) , 2008 .

[23]  Shi Ya,et al.  Preliminary Study on Signal, Impact and Foreground of Climatic Shift from Warm-Dry to Warm-Humid in Northwest China , 2002 .

[24]  Zhi Li,et al.  Changes in Central Asia’s Water Tower: Past, Present and Future , 2016, Scientific Reports.

[25]  Kenneth Hewitt,et al.  The Karakoram Anomaly? Glacier Expansion and the ‘Elevation Effect,’ Karakoram Himalaya , 2005 .

[26]  K. Fraedrich,et al.  Drought and wetness variability in the Tarim River Basin and connection to large‐scale atmospheric circulation , 2014 .

[27]  T. Zhou,et al.  Drought over East Asia: A Review , 2015 .

[28]  T. Bolch,et al.  The State and Fate of Himalayan Glaciers , 2012, Science.

[29]  T. Bolch,et al.  The Randolph Glacier inventory: a globally complete inventory of glaciers , 2014 .

[30]  Vijay P. Singh,et al.  SPI-based evaluation of drought events in Xinjiang, China , 2012, Natural Hazards.

[31]  V. Potop.  Evolution of drought severity and its impact on corn in the Republic of Moldova , 2011 .

[32]  Jianping Huang,et al.  Accelerated dryland expansion under climate change , 2016 .

[33]  T. McKee,et al.  THE RELATIONSHIP OF DROUGHT FREQUENCY AND DURATION TO TIME SCALES , 1993 .

[34]  W. Easterling,et al.  Measuring Drought Impacts: the Illinois Case , 1989 .

[35]  Assaf Anyamba,et al.  Global Trends in Seasonality of Normalized Difference Vegetation Index (NDVI), 1982-2011 , 2013, Remote. Sens..

[36]  Maosheng Zhao,et al.  Drought-Induced Reduction in Global Terrestrial Net Primary Production from 2000 Through 2009 , 2010, Science.

[37]  Pete Smith,et al.  Soil carbon stock and its changes in northern China's grasslands from 1980s to 2000s , 2010 .

[38]  Shu-long Yu,et al.  Tree‐ring‐based precipitation reconstruction in southern Kazakhstan, reveals drought variability since A.D. 1770 , 2017 .

[39]  Yaning Chen,et al.  Characteristics of drought in the arid region of northwestern China , 2015 .

[40]  Josef Soukup,et al.  Drought evolution at various time scales in the lowland regions and their impact on vegetable crops in the Czech Republic , 2012 .

[41]  D. Wilhite,et al.  Monitoring the 1996 Drought Using the Standardized Precipitation Index , 1999 .

[42]  Alessandro Anav,et al.  Global Data Sets of Vegetation Leaf Area Index (LAI)3g and Fraction of Photosynthetically Active Radiation (FPAR)3g Derived from Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI3g) for the Period 1981 to 2011 , 2013, Remote. Sens..

[43]  Shifeng Fang,et al.  Climate change and the ecological responses in Xinjiang, China: Model simulations and data analyses , 2013 .

[44]  E. Cook,et al.  The potential to reconstruct broadscale climate indices associated with southeast Australian droughts from Athrotaxis species, Tasmania , 2011 .

[45]  C. Tam,et al.  Six month–lead downscaling prediction of winter to spring drought in South Korea based on a multimodel ensemble , 2013 .

[46]  C. W. Thornthwaite.  An approach toward a rational classification of climate. , 1948 .

[47]  S. Vicente‐Serrano,et al.  A Multiscalar Drought Index Sensitive to Global Warming: The Standardized Precipitation Evapotranspiration Index , 2009 .

[48]  L. S. Pereira,et al.  Crop evapotranspiration : guidelines for computing crop water requirements , 1998 .

[49]  Vijay P. Singh,et al.  Assessment of drought vulnerability of the Tarim River basin, Xinjiang, China , 2015, Theoretical and Applied Climatology.

[50]  J. A. Schell,et al.  Monitoring vegetation systems in the great plains with ERTS , 1973 .