Description
This TRMM Visible and Infrared Scanner (VIRS) Level 1B Calibrated Radiance Product (1B01) contains calibrated radiances and auxiliary geolocation information from the five channels of the VIRS instrument, for each pixel of each scan. The data are stored in the Hierarchical Data Format (HDF), which includes both core and product specific metadata applicable to the VIRS measurements. A file contains a single orbit of data with a file size of about 95 MB. The EOSDIS "swath" structure is used to accommodate the actual geophysical data arrays. There are 16 files of VIRS 1B01 data produced per day.
For channels 1 and 2, Level 1B radiances are derived from the Level 1A (1A01) sensor counts by computing calibration parameters (gain and offset) derived from the counts registered during space and solar and/or lunar views. New calibration parameters are produced every one to four weeks. Channels 3, 4, and 5 are calibrated using the internal blackbody and the space view. These calibration parameters, together with a quadratic term determined pre-launch, are used to generate a counts vs. radiance curve for each band, which is then used to convert the earth-view pixel counts to spectral radiances.
Geolocation and channel data are written out for each pixel along the scan, whereas the time stamp, scan status (containing scan quality information), navigation, calibration coefficients, and solar/satellite geometry are specified on a per-scan basis. There are in general 18026 scans along the orbit pre-boost and 18223 post-boost, with each scan consisting of 261 pixels. The scan width is about 720 km pre-boost and 833 km post-boost.
Changes in horizontal resolution resulting from the TRMM boost that occurred on 24 August 2001:
Pre-Boost (before 7 August 2001): Temporal Resolution: 91.5 min/orbit ~ 16 orbits/day; Swath Width: 720 km; Horizontal Resolution: 2.2 km
Post-Boost (after 24 August 2001): Temporal Resolution: 92.5 min/orbit ~ 16 orbits/day; Swath Width: 833 km; Horizontal Resolution: 2.4 km
Resources
| Name | Format | Description | Link |
|---|---|---|---|
| Download this dataset through a directory map | HTML | Access the data via HTTPS | Open resource |
| View this dataset's read me document | README Document | Open resource | |
| Use OPeNDAP to access the dataset's data | HTML | Access the data via the OPeNDAP protocol. | Open resource |
| This dataset's landing page | HTML | Access the dataset landing page from the GES DISC website. | Open resource |
| Get a related visualization | PNG | TRMM_1B01_7.png | Open resource |
| View documentation related to this dataset | HTML | TRMM Data Gaps | Open resource |
| View documentation related to this dataset | File specification document. | Open resource | |
| View documentation related to this dataset | Comparison between TRMM versions 6 and 7. | Open resource | |
| Download this dataset through Earthdata Search | HTML | Use the Earthdata Search to find and retrieve data sets across multiple data centers. | Open resource |
| The dataset's project home page | HTML | TRMM Project Home Page | Open resource |