Negative soil moisture-precipitation feedback in dry and wet regions

Abstract

Soil moisture-precipitation (SM-P) feedback significantly influences the terrestrial water and energy cycles. However, the sign of the feedback and the associated physical mechanism have been debated, leaving a research gap regarding global water and climate changes. Based on Koster’s framework, we estimate SM-P feedback using satellite remote sensing and ground observation data sets. Methodologically, the sign of the feedback is identified by the correlation between monthly soil moisture and next-month precipitation. The physical mechanism is investigated through coupling precipitation and soil moisture (P-SM), soil moisture ad evapotranspiration (SM-E) and evapotranspiration and precipitation (E-P) correlations. Our results demonstrate that although positive SM-P feedback is predominant over land, non-negligible negative feedback occurs in dry and wet regions. Specifically, 43.75% and 40.16% of the negative feedback occurs in the arid and humid climate zones. Physically, negative SM-P feedback depends on the SM-E correlation. In dry regions, evapotranspiration change is soil moisture limited. In wet regions, evapotranspiration change is energy limited. We conclude that the complex SM-E correlation results in negative SM-P feedback in dry and wet regions, and the cause varies based on the environmental and climatic conditions.

A tale of two futures: contrasting scenarios of future precipitation for West Africa from an ensemble of regional climate models

“…The importance of land-atmosphere coupling in climate variability and change has been highlighted in many studies (e.g. Koster et al 2004, Seneviratne et al 2010, Yang et al 2018. In particular, the soil moisture (SM) feedback and coupling with evapotranspiration have been analysed at the global scale by Berg and Sheffield (2018) and specifically over Africa by Berg et al (2017).…”

“…Another mechanism controlling precipitation variability and change is the coupling between land and atmosphere, especially in transition zones between wet and dry climates where precipitation is closely dependent on soil moisture (Koster et al 2004, Taylor 2008, Seneviratne et al 2010, Berg et al 2017, Yang et al 2018.…”

Characterizing satellite‐derived soil moisture and its relationship with rainfall over India

“…The basic positive feedback mechanism between soil moisture and precipitation is an essential influence on climate. In addition, the hypotheses put forward by many modelling experiments (Asharaf et al, 2012;Guillod et al, 2015;Yang et al, 2018) show that a negative feedback prevails between soil moisture and precipitation. A large-scale soil moisture increase in the pre-monsoon season could dampen the monsoonal moisture transport from ocean to the Indian subcontinent.…”

“…The wet soil moisture anomalies increase the moist static energy by decreasing Bowen's ratio and surface albedo, which leads to increase in rainfall (Eltahir, ; Zheng and Eltahir, ). It is also notable that some of the recent modelling studies suggest a negative precipitation–soil moisture feedback persists over arid and humid regions (Guillod et al ., ; Yang et al ., ). Spatial heterogeneity in soil moisture is also affecting the convective activities of a region (Chang and Wetzel, ; Vezhapparambu, ).…”

Response to reviewer (RC1)

“…Printer-friendly version Discussion paper increase in evapotranspiration or precipitation due to soil moisture suctioning (Seneviratne et al, 2010;Yang et al, 2018). It is more likely that the latter process is occurring over the Amazon while the former is occurring over equatorial Africa given the seasonal occurrence of dry and wet soil moisture conditions shown over these regions in Figure 5.…”