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Relation between convective rainfall properties and antecedent soil moisture heterogeneity conditions in North Africa

(2018) REMOTE SENSING. 10(6).
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Abstract
Recent observational studies have demonstrated the relevance of soil moisture heterogeneity and the associated thermally-induced circulation on deep convection and rainfall triggering. However, whether this dynamical mechanism further influences rainfall propertiessuch as rain volume or timinghas yet to be confirmed by observational data. Here, we analyze 10 years of satellite-based sub-daily soil moisture and precipitation records and explore the potential of strong spatial gradients in morning soil moisture to influence the properties of afternoon rainfall in the North African region, at the 100-km scale. We find that the convective rain systems that form over locally drier soils and anomalously strong soil moisture gradients have a tendency to initiate earlier in the afternoon; they also yield lower volumes of rain, weaker intensity and lower spatial variability. The strongest sensitivity to antecedent soil conditions is identified for the timing of the rain onset; it is found to be correlated with the magnitude of the soil moisture gradient. Further analysis shows that the early initiation of rainfall over dry soils and strong surface gradients yet requires the presence of a very moist boundary layer on that day. Our findings agree well with the expected effects of thermally-induced circulation on rainfall properties suggested by theoretical studies and point to the potential of locally drier and heterogeneous soils to influence convective rainfall development. The systematic nature of the identified effect of soil moisture state on the onset time of rainstorms in the region is of particular relevance and may help foster research on rainfall predictability.
Keywords
BOUNDARY-LAYER INTERACTIONS, LARGE-EDDY SIMULATIONS, LAND-SURFACE, WEST-AFRICA, UNITED-STATES, PRECIPITATION FEEDBACK, OBSERVATIONAL, EVIDENCE, PASSIVE MICROWAVE, DIURNAL CYCLES, AMMA CAMPAIGN, soil moisture-precipitation coupling, soil moisture heterogeneity, convective rainfall initiation, semi-arid Sahel

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Chicago
Petrova, Irina Y, Diego Gonzalez Miralles, Chiel C van Heerwaarden, and Hendrik Wouters. 2018. “Relation Between Convective Rainfall Properties and Antecedent Soil Moisture Heterogeneity Conditions in North Africa.” Remote Sensing 10 (6).
APA
Petrova, I. Y., Gonzalez Miralles, D., van Heerwaarden, C. C., & Wouters, H. (2018). Relation between convective rainfall properties and antecedent soil moisture heterogeneity conditions in North Africa. REMOTE SENSING, 10(6).
Vancouver
1.
Petrova IY, Gonzalez Miralles D, van Heerwaarden CC, Wouters H. Relation between convective rainfall properties and antecedent soil moisture heterogeneity conditions in North Africa. REMOTE SENSING. 2018;10(6).
MLA
Petrova, Irina Y et al. “Relation Between Convective Rainfall Properties and Antecedent Soil Moisture Heterogeneity Conditions in North Africa.” REMOTE SENSING 10.6 (2018): n. pag. Print.
@article{8569419,
  abstract     = {Recent observational studies have demonstrated the relevance of soil moisture heterogeneity and the associated thermally-induced circulation on deep convection and rainfall triggering. However, whether this dynamical mechanism further influences rainfall propertiessuch as rain volume or timinghas yet to be confirmed by observational data. Here, we analyze 10 years of satellite-based sub-daily soil moisture and precipitation records and explore the potential of strong spatial gradients in morning soil moisture to influence the properties of afternoon rainfall in the North African region, at the 100-km scale. We find that the convective rain systems that form over locally drier soils and anomalously strong soil moisture gradients have a tendency to initiate earlier in the afternoon; they also yield lower volumes of rain, weaker intensity and lower spatial variability. The strongest sensitivity to antecedent soil conditions is identified for the timing of the rain onset; it is found to be correlated with the magnitude of the soil moisture gradient. Further analysis shows that the early initiation of rainfall over dry soils and strong surface gradients yet requires the presence of a very moist boundary layer on that day. Our findings agree well with the expected effects of thermally-induced circulation on rainfall properties suggested by theoretical studies and point to the potential of locally drier and heterogeneous soils to influence convective rainfall development. The systematic nature of the identified effect of soil moisture state on the onset time of rainstorms in the region is of particular relevance and may help foster research on rainfall predictability.},
  articleno    = {969},
  author       = {Petrova, Irina Y and Gonzalez Miralles, Diego and van Heerwaarden, Chiel C and Wouters, Hendrik},
  issn         = {2072-4292},
  journal      = {REMOTE SENSING},
  language     = {eng},
  number       = {6},
  pages        = {24},
  title        = {Relation between convective rainfall properties and antecedent soil moisture heterogeneity conditions in North Africa},
  url          = {http://dx.doi.org/10.3390/rs10060969},
  volume       = {10},
  year         = {2018},
}

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