Influence of Soil Moisture Anomaly on Temperature in the Sahel: A Comparison between Wet and Dry Decades

M. Shinoda Department of Geography, Tokyo Metropolitan University, Tokyo, Japan

Search for other papers by M. Shinoda in
Current site
Google Scholar
PubMed
Close
and
Y. Yamaguchi Department of Geography, Tokyo Metropolitan University, Tokyo, Japan

Search for other papers by Y. Yamaguchi in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

The influence of the Sahelian drought and resultant soil moisture deficit on air temperature is explored, using a simple water balance model that was validated with multiyear observations of the root-zone soil moisture. A comparison between wet soil years in the 1950s to 1960s and dry soil years in the 1970s to 1980s demonstrated a series of processes by which precipitation anomalies during the rainy season of a few months influence the time-lagging temperature through soil moisture. These processes were clearly seen only during the beginning 1 or 2 months of the dry season, and then both the concurrent soil moisture and temperature anomalies disappeared. Thus, the timescale of the drying up of root-zone soil moisture anomalies was determined to be approximately 1.5 months. This suggests that the root-zone soil moisture does not act as a memory of rainfall anomaly into the following rainy season and is not related to the long-term persistence of the drought.

Current affiliation: Applied Technology Co., Ltd., Tokyo, Japan

Corresponding author address: Masato Shinoda, Department of Geography, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan. Email: shinoda@comp.metro-u.ac.jp

Abstract

The influence of the Sahelian drought and resultant soil moisture deficit on air temperature is explored, using a simple water balance model that was validated with multiyear observations of the root-zone soil moisture. A comparison between wet soil years in the 1950s to 1960s and dry soil years in the 1970s to 1980s demonstrated a series of processes by which precipitation anomalies during the rainy season of a few months influence the time-lagging temperature through soil moisture. These processes were clearly seen only during the beginning 1 or 2 months of the dry season, and then both the concurrent soil moisture and temperature anomalies disappeared. Thus, the timescale of the drying up of root-zone soil moisture anomalies was determined to be approximately 1.5 months. This suggests that the root-zone soil moisture does not act as a memory of rainfall anomaly into the following rainy season and is not related to the long-term persistence of the drought.

Current affiliation: Applied Technology Co., Ltd., Tokyo, Japan

Corresponding author address: Masato Shinoda, Department of Geography, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan. Email: shinoda@comp.metro-u.ac.jp

Save
  • Chang, F-C., and Wallace J. M. , 1987: Meteorological conditions during heat waves and droughts in the United States Great Plains. Mon. Wea. Rev., 115 , 12531269.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Charney, J. G., 1975: Dynamics of deserts and drought in the Sahel. Quart. J. Roy. Meteor. Soc., 101 , 193202.

  • Cuenca, R. H., and Coauthors. 1997: Soil measurements during HAPEX-Sahel intensive observation period. J. Hydrol., 188/189 , 224266.

  • Delworth, T., and Manabe S. , 1988: The influence of potential evaporation on the variabilities of simulated soil wetness and climate. J. Climate, 1 , 523547.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Delworth, T., and Manabe S. , 1989: The influence of soil wetness on near-surface atmospheric variability. J. Climate, 2 , 14471462.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Durre, I., Wallace J. M. , and Lettenmaier D. P. , 2000: Dependence of extreme daily maximum temperatures on antecedent soil moisture in the contiguous United States during summer. J. Climate, 13 , 26412651.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Entekhabi, D., Rodriguez-Iturbe I. , and Bras R. L. , 1992: Variability in large-scale water balance with land surface–atmosphere interaction. J. Climate, 5 , 798813.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Entekhabi, D., Rodriguez-Iturbe I. , and Castelli F. , 1996: Mutual interaction of soil moisture and atmospheric processes. J. Hydrol., 184 , 317.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Entin, J. K., Robock A. , Vinnikov K. Y. , Hollinger S. E. , Liu S. , and Namkhai A. , 2000: Temporal and spatial scales of observed soil moisture in the extratropics. J. Geophys. Res., 105 , 1186511877.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • FAO-UNESCO, 1977: Africa. Vol. VI, Soil Map of the World, UNESCO, 299 pp.

  • Folland, C. K., Palmer T. N. , and Parker D. E. , 1986: Sahel rainfall and worldwide sea temperatures, 1901–85. Nature, 320 , 602607.

  • Gaze, S. R., Brouwer J. , Simmonds L. P. , and Bromley J. , 1998: Dry season water use patterns under Guiera senegalensis L. shrubs in a tropical savanna. J. Arid Environ., 40 , 5367.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Georgakakos, K. P., Bae D-H. , and Cayan D. R. , 1995: Hydroclimatology of continental watersheds. 1. Temporal analyses. Water Resour. Res., 31 , 655675.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hanan, N. P., and Prince S. D. , 1997: Stomatal conductance of West-Central Supersite vegetation in HAPEX-Sahel: Measurements and empirical models. J. Hydrol., 188/189 , 536562.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hastenrath, S., 1990: Decadal-scale changes of the circulation in the tropical Atlantic sector associated with Sahel drought. Int. J. Climatol., 10 , 459472.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Huang, J., Van den Dool H. M. , and Georgakakos K. P. , 1996: Analysis of model-calculated soil moisture over the United States (1931–1993) and applications to long-range temperature forecasts. J. Climate, 9 , 13501362.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Iwashita, H., Shinoda M. , and Moussa L. , 1999: Multi-year observations of soil moisture and pearl millet phenology at three sites in the Sahelian Niger. Human Response to Drastic Change of Environments in Africa, N. Hori, Ed., Tokyo Metropolitan University, 33–51.

    • Search Google Scholar
    • Export Citation
  • Janicot, S., Moron V. , and Fontaine B. , 1996: Sahel droughts and ENSO dynamics. Geophys. Res. Lett., 23 , 515518.

  • Karl, T. R., 1986: The relationship of soil moisture parameterizations to subsequent seasonal and monthly mean temperature in the United States. Mon. Wea. Rev., 114 , 675686.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Koster, R. D., and Suarez M. J. , 2001: Soil moisture memory in climate models. J. Hydrometeor., 2 , 558570.

  • Lare, A. R., and Nicholson S. E. , 1994: Contrasting conditions of surface water balance in wet years and dry years as a possible land surface–atmosphere feedback mechanism in the West African Sahel. J. Climate, 7 , 653668.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mintz, Y., and Walker G. K. , 1993: Global fields of soil moisture and land surface evapotranspiration derived from observed precipitation and surface air temperature. J. Appl. Meteor., 32 , 13051334.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nicholson, S. E., and Grist J. P. , 2001: A conceptual model for understanding rainfall variability in the West African Sahel on interannual and interdecadal timescales. Int. J. Climatol., 21 , 17331757.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nicholson, S. E., Marengo J. A. , Kim J. , Lare A. R. , Galle S. , and Kerr Y. H. , 1997: A daily resolution evapoclimatonomy model applied to surface water balance calculations at the HAPEX-Sahel supersites. J. Hydrol., 188/189 , 946964.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Penman, H. L., 1963: Vegetation and hydrology. Tech. Publ. 53, Commonwealth Bureau of Soils, Harpenden, United Kingdom, 125 pp.

  • Peterson, T. C., and Vose R. S. , 1997: An overview of the Global Historical Climatology Network temperature database. Bull. Amer. Meteor. Soc., 78 , 28372849.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rowell, D. P., 1996: Further analysis of simulated interdecadal and interannual variability of summer rainfall over tropical north Africa. Quart. J. Roy. Meteor. Soc., 122 , 10071013.

    • Search Google Scholar
    • Export Citation
  • Shinoda, M., and Kawamura R. , 1994: Tropical rainbelt, circulation, and sea surface temperatures associated with the Sahelian rainfall trend. J. Meteor. Soc. Japan, 72 , 341357.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shinoda, M., and Gamo M. , 2000: Interannual variations of boundary layer temperature over the African Sahel associated with vegetation and the upper troposphere. J. Geophys. Res., 105 , 1231712327.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shinoda, M., Okatani T. , and Saloum M. , 1999: Diurnal variations of rainfall over Niger in the West African Sahel: A comparison between wet and drought years. Int. J. Climatol., 19 , 8194.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shinoda, M., Iwashita H. , and Moussa L. , 2002: Updated time series of soil moisture and leaf area index in Niger. Observational Study on the Vegetation–Soil Moisture–Atmosphere, M. Shinoda, Ed., Tokyo Metropolitan University, 4–11.

    • Search Google Scholar
    • Export Citation
  • Soil Survey Staff, 1962: Soil Survey Manual. U.S. Dept. of Agriculture, 503 pp.

  • Taylor, C. M., Saïd F. , and Lebel T. , 1997: Interactions between the land surface and mesoscale rainfall variability during HAPEX-Sahel. Mon. Wea. Rev., 125 , 22112227.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Thornthwaite, C. W., 1948: An approach toward a rational classification of climate. Geogr. Rev., 38 , 5594.

  • Vinnikov, K. Y., and Yeserkepova I. B. , 1991: Soil moisture: Empirical data and model results. J. Climate, 4 , 6679.

  • Vinnikov, K. Y., Robock A. , Speranskaya N. A. , and Schlosser C. A. , 1996: Scales of temporal and spatial variability of midlatitude soil moisture. J. Geophys. Res., 101 , 71637174.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Vose, R. S., Schmoyer R. L. , Steurer P. M. , Peterson T. C. , Heim R. , Karl T. R. , and Eischeid J. K. , 1992: The Global Historical Climatology Network: Long-term monthly temperature, precipitation, sea level pressure, and station pressure data. ORNL/CDIAC-53, NDP-041, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, 315 pp.

    • Search Google Scholar
    • Export Citation
  • Walsh, J. E., Jasperson W. H. , and Ross B. , 1985: Influences of snow cover and soil moisture on monthly air temperatures. Mon. Wea. Rev., 113 , 756768.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, G., and Eltahir E. A. B. , 2000: Role of vegetation dynamics in enhancing the low-frequency variability of the Sahel rainfall. Water Resour. Res., 36 , 10131021.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Williams, K. R. S., 1992: Correlations between Palmer drought indices and various measures of air temperature in the climatic zones of the United States. Phys. Geogr., 13 , 349367.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wolter, K., 1989: Modes of tropical circulation, Southern Oscillation, and Sahel rainfall anomalies. J. Climate, 2 , 149172.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xue, Y., and Shukla J. , 1993: The influence of land surface properties on Sahel climate. Part I: Desertification. J. Climate, 6 , 22322245.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yamaguchi, Y., and Shinoda M. , 2002: Soil moisture modeling based on multiyear observations in the Sahel. J. Appl. Meteor., 41 , 11401146.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zeng, N., Neelin J. D. , Lau K-M. , and Tucker C. J. , 1999: Enhancement of interdecadal climate variability in the Sahel by vegetation interaction. Science, 286 , 15371540.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 339 44 2
PDF Downloads 139 27 0