Monitoring agricultural drought with climate-based drought indices in China

Abstract:

Agricultural drought monitoring significantly influences food security in recent decades. Soil moisture shortages adversely affecting agriculture is one important indicator for agricultural drought monitoring. Because of limited soil moisture observations, characterizing soil moisture using climate-based drought indices has great practical meaning. The agricultural area in China was identified by crop identification from remotely sensed data. Drought indices of multiple timescale or from two-layer bucket model were analyzed. In most agricultural areas of China, surface soil moisture is more affected by drought indices having shorter time scales while deep-layer soil moisture is more related on longer time scales. In general, multiscalar drought indices work better than drought indices from two-layer bucket models. The standardized precipitation evapotranspiration index (SPEI) works similarly or better than the standardized precipitation index (SPI) in characterizing soil moisture at different soil layers. In most stations in China, the Z index has a higher correlation with soil moisture at 0–5 cm than the Palmer drought severity index (PDSI), which in turn has a higher correlation with soil moisture at 90–100-cm depth than the Z index. Soil moisture–drought indices relationship was significantly affected by soil organic carbon density. Effective agriculture drought monitoring can be conducted with climate-based drought indices from widely available climatic data and crop area identification from remote sensing.

Authors:Hongshuo wang1, Chao Zhang1, Jeffery C Rogers2

1 China agricultural university

2 Ohio state University

Key words: Agricultural drought, SPI, SPEI, PDSI, Z index, crop identification