Centennial drought outlook over the CONUS using NASA‐NEX downscaled climate ensemble

Abstract

Drought is a natural hazard developing slowly and affecting large areas which may have severe consequences on society and economy. Due to the effects of climate change, drought is expected to exacerbate in various regions in future. In this study, the impact of climate change on drought characteristics is assessed, and statistical methods are employed to analyse the significance of projections. This is the first study utilizing 21 recently available downscaled global climate models generated by NASA (NEX‐GDDP) to evaluate drought projections over various regions across the United States. Drought is investigated through a multi‐model dual‐index dual‐scenario approach to probabilistically analyse drought attributes while characterizing the uncertainty in future drought projections. Standardized Precipitation Index and Standardized Precipitation Evapotranspiration Index values at the seasonal scale (3 months) are used to project and analyse meteorological drought conditions from 1950 to 2099 at 0.25° spatial resolution. Two future concentration pathways of RCP4.5 and RCP8.5 are considered for this analysis. Accounting for the combined effects of precipitation and temperature variations reveals a considerable aggravation in severity and extent of future drought in the western United States and a tendency toward more frequent and intense summer droughts across the Contiguous United States.

Apprehensive Drought Characteristics over Iraq: Results of a Multidecadal Spatiotemporal Assessment

“…In the present study, PET depends on temperature and thus SPEI can be affected indirectly by temperature and directly by PET and P [10]. Therefore, it is of high importance to understand the contribution of these factors on drought.…”

“…A drought event is defined when the SPEI falls below −1 (moderate drought condition or worse) and stays within dry threshold for more than two months. Similar procedure has been utilized in previous researches to assess drought frequency (e.g., Ahmadalipour et al [10] and Van Loon, A. F. [68]). Drought duration is defined for each grid as the accumulative period of dry months experiencing each of the three types of drought (i.e., moderate, severe and extreme).…”

“…The non-parametric approach relaxes such issues of the conventional methods and removes the subjectivity in the calculations [7]. Therefore, a non-parametric approach is more practical to use and more suitable for this study since the focus is on all drought types and not only the extreme drought [10]. In this study, the empirical Weibull plotting position [66,67] is used as a non-parametric approach as shown in Equation (4):…”

“…Drought is generally categorized to four types including: (1) Meteorological drought which is primarily related to precipitation deficit [8][9][10]; (2) Agricultural drought which is mainly related to soil moisture shortage [11][12][13][14][15]; (3) Hydrological drought which is associated with surface and subsurface water shortfall [16][17][18][19][20][21][22]; (4) Socioeconomic drought which is related to a deficiency in the water resources system as a result of the other drought types [1,[23][24][25]. The aforementioned drought types constitute the same process but under distinct phases as a function of time and location [26].…”

Drought Evolution Due to Climate Change and Links to Precipitation Intensity in the Haihe River Basin

“…Analyses predominantly involve the drought evaluation index method, which uses one or more drought indexes based on long-term meteorological observations to demonstrate drought evolution laws [4][5][6][7][8][9][10][11][12][13][14]; the simulation method, which combines drought evaluation indexes with climate models [15,16] and hydrologic models [17,18] to simulate drought variability; and remote sensing methods, which use remote sensing data to assess spatiotemporal variations [19][20][21]. As precipitation extremes give rise to flooding and droughts, the impact of climate change is receiving considerable attention, and many studies show that extreme precipitation events will become more common in a warmer climate [22][23][24][25][26].…”