1. Accessing Global Precipitation Data Products via TRMM Online Visualization and Analysis System (TOVAS)
Zhong Liu
Center for Spatial Information Science and Systems (CSISS), George Mason University
and
NASA Goddard Earth Sciences Data and Information Services Center (GES DISC)

2. Outline Brief overview of TRMM Introduction of TOVAS
Precipitation products in TOVAS
TOVAS interface overview
Functions and examples
Other ancillary tools
Future plans
Other TRMM data and services at GES DISC
Demos and hands-on exercises
Questions

3. Brief Overview of TRMM Tropical Rainfall Measuring Mission (TRMM)
Sampling footprint between 35°S and 35°N
4-D distribution of rainfall and latent heating over vastly under-sampled oceanic and tropical continental regimes

4. GES DISC is the TRMM data archive center
PR – 247Km (5km)
TMI – 878km (5.1km, 85.5GHz)
VIRS – 833 km (2.4km)
GES DISC is the TRMM data archive center
Courtesy of trmm.gsfc.nasa.gov

5. TOVAS Introduction
Why TOVAS?

6. Traditional Way vs. TOVAS in Data Evaluation for a New User
Basic analysis and visualization (no software and data download needed)
Traditional Way:
Obtain data from a FTP site
Read data manuals
Learn software if available
If not available, write your own software
Write visualization software

7. TOVAS

8. Visualization and Analysis Server
Reliable
Flexible
Low-cost
System Description
Visualization and Analysis Server
Receive Parameters from Interface CGI
Output to Web Browser
GrADS Environment
Compose GrADS Script
Execute GrADS Script
Generate Plot/ASCII Output
Receive Parameters from Web Client
Output to Web Client
Data: Binary or GDS
GrADS: The Grid Analysis and Display System (COLA)

9. Products in TOVAS Near-real-time Rainfall Archives
Ground Observation Archives
Other Ancillary Products

10. Near-real-time
3-Hourly combined (3B42RT)
3-Hourly microwave (3B40RT)
Hourly IR (3B41RT)
Daily (derived from 3B42RT)

11. Rainfall Archives
3-Hourly (3B42)
Daily (derived from 3B42)
10-day (derived from 3B42)
Monthly (3B43, 3A12, 3A25, GPCP, etc.)

12. Ground Observation Archives
Willmott ( , 0.5 deg)
GPCC (1986 – present, 1 deg)

13. Others: •Monthly Global Precipitation (GPCP)
• Prototype Interactive Inter-comparison of Rainfall Products
• Monthly Rainfall (3B43 V6) Anomaly
• Inter-Comparison of Rainfall Climatology

14. TRMM Web Interface Overview

15. TOVAS Landing Page: http://disc2.nascom.nasa.gov/Giovanni/tovas/
New

16. Two types of GUIs

20. Accessing new interfaces:

26. TOVAS Functions and Examples

27. TOVAS Functions:
Animation
Lat-Lon Area Plot, Time-averaged
Lat-Lon Plot, Difference Map
Latitude-Time Hovmöller Plot
Longitude-Time Hovmöller Plot
Correlation Plot
Comparison Plot
Cross-Map Plot (Latitude-Height)
Cross-Map Plot (Longitude-Height)
Cross-Map Plot (Time-Height)
Scatter Plot
Scatter Plot, Time-averaged
Time Series, Area-averaged
Time Series Difference
Time Series, Area Statistics

28. Other Features: Climatology Anomaly and normalized anomaly
Fine tune graphic output
Output in other formats (e.g., NetCDF)
Google Earth KMZ file output
Application examples with real events
FAQ and documentation
Help desk

29. 2D Lat-Lon Plots (Record breaking rainfall in the Mid-Atlantic Region in 2003)

30. 2D Plots (The contribution of Isabel in 2003)

31. Time Series Plots Mid- Atlantic Region Alex, Charley, Gaston Floyd
Isabel
Mid- Atlantic Region

32. Hovmoller Diagram (Mid-Atlantic Region)
Multiple Tropical Storms
Isabel
Floyd

33. Anomaly (Positive anomaly due to Isabel in Sept., 2003)

34. Scatter Plot (Error vs Rain Rate, revealing biases)

35. ASCII data output for further analysis (e.g. MS. Excel)

36. Prototype Interactive Inter-comparison of Rainfall Products

39. Other Ancillary Tools Hurricane Data Analysis Tool (HDAT)
Other Giovanni Tools

40. Hurricane Data Analysis Tool: http://disc.gsfc.nasa.gov/HDAT
The global merged IR product, also known as, the NCEP/CPC 4km Global (60ºN - 60ºS) IR Dataset, is one of TRMM ancillary datasets.
4 km IR
Global (60ºN - 60ºS)
30 minutes
Since Feb., 2000

41. Basic Functions and Features:
Selection of area of interest
Single image or multiple images (animation)
Allow time skipping (1 hr., 2 hr., etc.)
Allow different image sizes
False color
Fine tune graphic output

42. HDAT Landing Page

43. HDAT Landing Page (Cont.):

44. HDAT Landing Page (Cont.):

45. HDAT Landing Page (Cont.):

46. Examples: Category 2 cyclone Catarina – Landfall

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

48. Dust Strom (near Iraq and Saudi Arabia border)

49. Dust Storm (cont.)

50. TOVAS and HDAT
2009
2010
Flooding in Pakistan due to higher-than-normal monsoon rainfall between Jul – Aug. 2010

53. Other Giovanni Tools: http://disc.sci.gsfc.nasa.gov/giovanni
Giovanni: GES-DISC (Goddard Earth Sciences Data and Information Services Center) Interactive Online Visualization ANd aNalysis Infrastructure

55. Cloud Water in g/m3 (scaled by 100)
Cloud Ice in g/m3 (scaled by 100)
Precipitation Ice in g/m3 (scaled by 100)

56. Future Plans for TOVAS:
Add more functions
IPWG: a proposal for adding IPWG validation algorithms is pending
Add TRMM Level-2 orbital data (a prototype to extract 2A12 and 2A25 profiles is ready for YOTC)
Add multi-sensor data (e.g., CloudSat)

57. Other TRMM data and services at GES DISC
Mirador
Other data accessing methods

58. TRMM Data Archive at GES DISC

59. Data Volumes (as of Sept. 22, 2010)
Standard products (L-1, L-2, L-3, orbital, gridded): ~20.3 TB (772,553 files)
Ancillary data: ~1.9 TB (93,051 files)
Ground based instruments: ~4.5 TB (1,853,484)
Subsets: ~3.1 TB (2,995,019)
File Total: 5,714,107
Total size: ~29.7 TB

60. Mirador Basic Features: http://mirador.gsfc.nasa.gov/
Search features: Keyword/event search, projects, science focus areas
Spatial subsetting (limited products)
Format conversion (e.g., NetCDF)

61. Other Data Access Methods:
Giovanni TOVAS (TRMM Online Visualization and Analysis System)
GrADS Data Server (GDS) (subsetting and analysis services over the Internet)
OPeNDAP (accessed by IDL, GrADS)
The Open Geospatial Consortium (OGC) Web Map Server (WMS)
Google Earth

62. Demos and Hands-on Exercises

63. Generate a lat-lon map
Generate a time series and its ASCII data
New interface and data download options

64. URLs: Contact: Zhong.Liu@nasa.gov
TOVAS:
HDAT:
Mirador:
Giovanni:
GES DISC:
Contact:

65. Thank You!