1 / 19

Benjamin L. Lamptey February 1, 2007

Comparison of gridded multi-satellite rainfall estimates with gridded gauge rainfall over West Africa. Benjamin L. Lamptey February 1, 2007. Motivation. Usefulness of satellite imagery Rainfall estimation over areas with a low density of rain gauges

nishan
Download Presentation

Benjamin L. Lamptey February 1, 2007

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Comparison of gridded multi-satellite rainfall estimates with gridded gauge rainfall over West Africa Benjamin L. Lamptey February 1, 2007

  2. Motivation • Usefulness of satellite imagery • Rainfall estimation over areas with a low density of rain gauges • in providing data with spatial resolution closer to that of the numerical models • Flood warnings, river estimates or water management • Extent to which satellite can be relied upon to give a good database needed for the analysis of rainfall variability

  3. Datasets • GPCC (VASClimO) • Sources include CRU, FAO, GHCN, GTS (over 27,000 stations) • Global dataset • GPCP • Sources geo-IR (from NOAA and NCEP), microwave • Covered 40degN to 40degS • Period of analysis:1979 - 2000 • Resolution is 2.5deg by 2.5deg

  4. Regions in Study Domain

  5. Areas of comparison • Mean annual, seasonal and monthly rainfall • Spatial variability over the domain at the annual and seasonal time scales • Inter annual variability in the three regions • The mean state and fluctuations during El Nino and La Nina events • Trends in either dataset

  6. Annual Climatology

  7. Scatter plot (annual & seasonal)

  8. Annual Cycle

  9. Annual Cycle cont’d

  10. Annual Cycle cont’d

  11. Latitudinal Profile (zonal mean annual)

  12. Pattern Correlation

  13. Kendall’s tau • Gauge • Prob = 3.04E-05 • Satellite • Prob = 2.83E-02

  14. Seasonal Rainfall Statistics

  15. Interannual Variability

  16. Spatial variability

  17. El Nino/La Nina (Mean state)

  18. El Nino/La Nina (Std. Anom)

  19. Conclusion • The satellite can be relied upon for the climatology and inferences about latitudinal bands • Datasets agree more in the northern latitudes than in the southern latitudes • Both datasets indicate statistically significant trends • Satellite data indicates more rainfall over the highlands of Cameroon but less over the highlands of Guinea • Performance of satellite is no different during El Nino/La Nina events regarding spatial distribution

More Related