Online Inter-comparison of Satellite-derived Global Precipitation Products Zhong Liu1,2, Dana Ostrenga1,3, William Teng1,4, and Steven Kempler1 1Goddard Earth Sciences Data and Information Services Center (GES DISC) NASA Goddard Space Flight Center, Code 610.2, Greenbelt, MD, 20771, USA 2Center for Spatial Information Science and Systems (CSISS), George Mason University, USA 3ADNET Systems, Inc., USA 4Wyle Information Systems, Inc., USA

Outline Introduction Overview of inter-comparison effort at GES DISC Examples Future work Summary and URLs

Introduction NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) – TRMM product archive, data services, documentation and user support Product version changes (user defined ROI) Product differences (inter-comparison among different products) Discussion/suggestions during the 5th IPWG meeting

Overview of inter-comparison effort

In this talk:

3B43 (0.25 deg)

3B43

3B43

3B43

3A25 Version 6 TRMM satellite altitude was changed from 350 km to 402.5 km in August 2001

3A25 Version 7

3A25 Problem (Mar. 2011)

3A12 (0.5 deg.)

3A11 (5 deg.)

3B42 – 3B42RT Dry Wet Annual Big Island, Hawaii

Big Island, Hawaii 3B42 3B42RT Overlay Scatter

TRMM Composite Climatology (TCC) (TCC) consists of a merger of selected TRMM rainfall products over both land and ocean to give a "TRMM-best" climatological estimate. V6 only

Simple All products

Samples

Merged IR (recommended): The Hurricane Data Analysis Tool (HDAT) Landing Page

HDAT Landing Page (Cont.):

AF Flight-447: Satellite Observation of Mesoscale Convective System Development on 1 June, 2009

Future Plans Additional parameters products (mostly in monthly) To quantify inter-comparison results by adding the statistical methods found in, http://www.cawcr.gov.au/projects/verification/ (available in http://www.isac.cnr.it/~ipwg/)

Future Plans (Cont’) Estimated and observed rain area Hits, misses, false alarms, correct rejections (2x2 contingency table) Estimated and observed rain volume Bias score (ratio of estimated/observed rain frequency or area) Estimated and observed conditional rain rate Probability of detection Estimated and observed maximum rain rate False alarm ratio Mean absolute error Hanssen and Kuipers score Root mean square (RMS) error Equitable threat score Correlation coefficient Heidke skill score

Summary Online inter-comparison tools for precipitation products (mainly TRMM and TMPA, 3-hourly, daily, monthly and climatology), help revealing product characteristics An online tool to visualize and analyze the merged IR product Inputs from the IPWG community are very important for current and future work

Acknowledgements: The inter-comparison tools are supported by NASA Research Opportunities in Space and Earth Science- 2010 (ROSES-2010), NNH10ZDA001N-ESDRERR, Appendix A.32: "Earth System Data Records Uncertainty Analysis" and the NASA GES DISC. Special thanks to the Giovanni Team.

URLs: Contact: Zhong.Liu@nasa.gov TOVAS: http://disc2.nascom.nasa.gov/Giovanni/tovas/ HDAT: http://disc.sci.gsfc.nasa.gov/HDAT Mirador: http://mirador.gsfc.nasa.gov/ Giovanni: http://disc.sci.gsfc.nasa.gov/giovanni Current conditions: http://disc.sci.gsfc.nasa.gov/agriculture/additional/tools/current_conditions.shtml GES DISC: http://disc.sci.gsfc.nasa.gov/ Contact: Zhong.Liu@nasa.gov