Characterization of Drought Development through Remote Sensing: A Case Study in Central Yunnan, China

Abstract

This study assesses the applicability of remote sensing data for retrieval of key drought indicators including the degree of moisture deficiency, drought duration and areal extent of drought within different land cover types across the landscape. A Normalized Vegetation Supply Water Index (NVSWI) is devised, combining remotely sensed climate data to retrieve key drought indicators over different vegetation cover types and a lag-time relationship is established based on preceding rainfall. The results indicate that during the major drought event of spring 2010, Evergreen Forest (EF) experienced severe dry conditions for 48 days fewer than Cropland (CL) and Shrubland (SL). Testing of vegetation response to drought conditions with different lag-time periods since the last rainfall indicated a highest correlation for CL and SL with the 4th lag period (i.e., 64 days) whereas EF exhibited maximum correlation with the 5th lag period (i.e., 80 days). Evergreen Forest, which includes tree crops, appears to act as a green reservoir of water, and is more resistant than CL and SL to drought due to its water retention capacity with deeper roots to tap sub-surface water. Identifying differences in rainfall lag-time relationships among land cover types using a remote sensing-based integrated drought index enables more accurate drought prediction, and can thus assist in the development of more specific drought adaptation strategies.

Use of the Standardized Precipitation Evapotranspiration Index (SPEI) to Characterize the Drying Trend in Southwest China from 1982–2012

“…It could be found the most severe drought was recorded in the year of 2010 with several monthly regional-averaged SPEI approximating to −1.5. This severe drought has already been reported by numerous researches [27,28,35,[65][66][67]. The temporal evolution of SPI at 1-, 3-, 6-, 12-, and 24-month lags were also calculated (not shown), and its difference with SPEI at 1-and 3-month lags were shown in Figure 4.…”

Drought monitoring in the Brazilian Semiarid region

“…A number of drought indices, including meteorological (Wilhite and Glantz 1985), remote sensed, hydrological and other indicators, have been used to measure drought impacts (Palmer 1965, 1968, Kogan 1990, 2002, McKee et al 1993, Keyantash and Dracup 2004, Bhuiyan et al 2006, Yagci et al 2011, Zhou et al 2012, Du et al 2013, Yang et al 2013, Abbas et al 2014, Cunha et al 2015. Traditional methods of drought assessment and monitoring rely on rainfall data (e.g., Precipitation Percentile).…”

Stock Volume Dependency of Forest Drought Responses in Yunnan, China

“…Typical drought events in Yunnan include the mild drought of 2005 and the persistent drought in winter of 2009 to spring of 2010 [10,41]. Yunnan Province is currently a focus study region for exploring how the forest responds to drought as it has a high forest cover rate and has suffered several drought events [43,44], especially from 2001-2014. Due to all of these reasons, Yunnan Province was selected as the study region.…”