We have published three new papers on land-atmosphere interactions, and the soil moisture-precipitation feedback. The first paper Land-Atmosphere Interactions: The LoCo Perspective is published in BAMS, the American Meteorological Society's flagship journal. The paper presents an overview of the research that has been done under the umbrella of the GEWEX Local Coupling (LoCo) working group. Under the lead of Joe Santanello of NASA, the working group has been active in investigating the role of local land-atmosphere interactions in the global climate. The achievements of the LoCo group have clearly shown the necessity of the integrated study of the land surface, the atmospheric boundary layer, clouds, and precipitation.
The second and third paper are the resulting publications of the PhD work of my former student Irina Petrova, in combination with major contributions by the group of Diego Miralles at Ghent University. The paper in Hydrology and Earth System Science Regional co-variability of spatial and temporal soil moisture–precipitation coupling in North Africa: an observational perspective presents a study on soil-moisture precipitation coupling from satellite observations at an unprecedented spatial resolution of 1 degree.
The figure above summarizes our main findings. We confirm earlier findings of hotspots where locally drier soils show higher precipitation potential, as well as regions that show the opposite, with more rain over wetter soils. Furthermore, we show that in regions closer to the equator, rain is more likely to fall when the atmosphere is dry, but if we move closer to the Sahara desert, a moist atmosphere is required to allow rising moist plumes to retain sufficient moisture to generate precipitation.
Our paper in Remote Sensing Relation between Convective Rainfall Properties and Antecedent Soil Moisture Heterogeneity Conditions in North Africa contains an analysis of more than 16,000 rain storms in North Africa. While previous studies already showed that afternoon rain was more likely over relatively dry soils, we have extended our analysis to onset times of rain, as well as rain amount. We provide observational evidence that convective rain systems that a) form over locally drier soils and b) have anomalously strong spatial gradients in soil moisture, have a tendency to initiate earlier in the afternoon; they also yield lower volumes of rain, have a weaker intensity and a lower spatial variability.
Santanello Jr, J.A., Dirmeyer, P.A., Ferguson, C.R., Findell, K.L., Tawfik, A.B., Berg, A., Ek, M., Gentine, P., Guillod, B.P., van Heerwaarden, C. and Roundy, J., 2018. Land-Atmosphere Interactions: The LoCo Perspective. Bulletin of the American Meteorological Society, 99, 1253-1272, https://doi.org/10.1175/BAMS-D-17-0001.1
Petrova, I.Y., van Heerwaarden, C.C., Hohenegger, C. and Guichard, F., 2018. Regional co-variability of spatial and temporal soil moisture–precipitation coupling in North Africa: an observational perspective. Hydrology and Earth System Sciences, 22(6), 3275-3294, https://doi.org/10.5194/hess-22-3275-2018
Petrova, I.Y., Miralles, D.G., van Heerwaarden, C.C. and Wouters, H., 2018. Relation between Convective Rainfall Properties and Antecedent Soil Moisture Heterogeneity Conditions in North Africa. Remote Sens., 10, 969, https://doi.org/10.3390/rs10060969