AMMR Air and Brightness Temperature Data, Wakasa Bay

Summary

The Wakasa Bay Field Campaign was conducted in January and February 2003 to validate rainfall algorithms developed for the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E). The primary objective was to validate both AMSR and AMSR-E shallow rainfall and snowfall retrievals. An Airborne Multichannel Microwave Radiometer (AMMR) aboard a NASA P-3 Orion collected 37 GHz and 21 GHz brightness temperatures (T_Bs) and air temperatures on 14 January, 19 January, 21 January, and 03 February 2003. All measurements fall within 30.6763°N to 41.476°N, 134.0313°E to 150.3528°E. Data are in tab-delimited ASCII text format and are available via FTP.

Citing These Data

The following example shows how to cite the use of this data set in a publication. For more information, see our Use and Copyright Web page.

Wang, J. 2004. AMMR air and brightness temperature data, Wakasa Bay. Boulder, CO: National Snow and Ice Data Center. Digital media.

Overview Table

Table of Contents

1. Contacts and Acknowledgments
2. Detailed Data Description
3. Data Access and Tools
4. Data Acquisition and Processing
5. References and Related Publications
6. Document Information

1. Contacts and Acknowledgments

Investigator(s) Name and Title

James Wang
Code 975
NASA Goddard Space Flight Center
Greenbelt, MD  20771

Technical Contact

2. Detailed Data Description

This data set represents one in a series of aircraft campaigns to validate rainfall algorithms developed for the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E). The AMSR/AMSR-E Wakasa Bay Field Campaign was conducted over Wakasa Bay, Japan, in January and February 2003. The campaign was designed to:

1. Validate both AMSR and AMSR-E shallow rainfall and snowfall retrievals.

2. Extend the database of rainfall properties needed to implement a comprehensive physical validation scheme.

3. Extend understanding of rainfall structures through new remote sensing technology.

The Wakasa Bay Field Campaign was extended into 2003 with joint research observations by the Japan Aerospace Exploration Agency (JAXA, Contractor: Mitsubishi Electric Corporation), AMSR precipitation validation team, and the NASA AMSR-E team.

The experiment included several sensors aboard a NASA P-3 aircraft, an array of ground-based radars, and in-situ ground and airborne hydrometer observations provided by Japan's Core Research for Evolutional Science and Technology (CREST) program. The Airborne Multichannel Microwave Radiometer (AMMR) provided brightness temperature (T_B) measurements for this data set. Air temperature data come directly from the P-3 aircraft navigation data.

Format

Data are in tab-delimited ASCII text format with the following columns:

Year
Month
Day
Hour (UTC)
Minute
Second
21 GHz T_B (°C)
37 GHz T_B (°C)
Latitude (decimal degrees)
Longitude (decimal degrees)
Altitude (m)
Heading (decimal degrees)
Pitch (decimal degrees)
Roll (decimal degrees)
Air temperature (°C)

File Naming Convention

ammr3014.txt: 14 January 2003
ammr3019.txt: 19 January 2003
ammr3021.txt: 21 January 2003
ammr3034.txt: 03 February 2003

File Size

ammr3014.txt: 1.55 MB
ammr3019.txt: 1.99 MB
ammr3021.txt: 1.98 MB
ammr3034.txt: 1.64 MB

Spatial Coverage

Wakasa Bay is located north of Osaka in the Sea of Japan. Measurements fall within the following coordinates:

Southernmost Latitude: 30.6763°N
Northernmost Latitude: 41.476°N
Westernmost Longitude: 134.0313°E
Easternmost Longitude: 150.3528°E

Temporal Coverage

14 January 2003: 04:08:16 to 08:58:08 UTC
19 January 2003: 02:49:33 to 09:06:07 UTC
21 January 2003: 02:18:02 to 06:41:58 UTC
03 February 2003: 01:27:56 to 06:36:23 UTC

Temporal Resolution

Sampling resolution is once per second.

Parameter or Variable

Sample Data Record

Following are the first four lines of data from "ammr3014.txt." See the Format section for columns.

 2003    1   14    4    8   16   15.8   13.8  41.3527 139.1815   8159.75  201.22   -0.87   -3.51  -15.53
 2003    1   14    4    8   17   15.8   13.8  41.3517 139.1811   8143.25  200.99   -0.87   -3.28  -15.56
 2003    1   14    4    8   18   15.8   13.8  41.3507 139.1807   8127.25  200.76   -0.86   -3.06  -15.58
 2003    1   14    4    8   19   15.9   13.8  41.3496 139.1803   8106.75  200.56   -0.87   -2.87  -15.62

Quality Assessment

The T_B sensitivity is < 0.5 K, and calibration accuracy is about ± 4 K.

3. Data Access and Tools

Data Access

Data are available via FTP.

Volume

The complete data set is 7 MB.

Related Data Collections

• AMSR-E Validation Data

4. Data Acquisition and Processing

Sensor or Instrument Description

The AMMR sensor measures thermal microwave emission (in °C of T_B) from the surface and atmosphere. The up-looking radiometer at 21 and 37 GHz is a component of AMMR that was developed in the 1970's for precipitation measurements from an aircraft. The entire AMMR assembly covers a frequency range of 10 to 92 GHz. The 21/37 GHz unit has been flown in many types of aircraft during the past three decades in various field campaigns. It was refurbished during the year 2000 and is ready for flights again.

The fixed-beam Dicke radiometer has a beam width of about 6° and is currently programmed with radiometric output every second. The temperature sensitivity is < 0.5 K, and the calibration accuracy is about ±4 K. The calibration is performed on the ground by viewing targets of known brightness (e.g., sky and absorber with known brightness temperature). The unit is installed in one of the windows of the NASA P-3 aircraft so that it views at an angle of about 15° from zenith; thus, it is necessary to spiral the aircraft gradually down to a region below the freezing level in order to make measurements effectively. Ideally, the aircraft descends at the rate of about 1 km per 5 minutes. The system requires a bottle of N₂ gas to keep the wave guides dry during the in-flight operation.

5. References and Related Publications

"NASA Joins Snow Study over the Sea of Japan." 29 January 2003.
http://www.gsfc.nasa.gov/topstory/2003/0122japansnow.html.
Accessed March 2004.

"Wakasa Bay Field Experiment." AMSR - Rainfall Validation.
http://rain.atmos.colostate.edu/Wakasa/.
Accessed March 2004.

6. Document Information

Acronyms and Abbreviations

The following acronyms and abbreviations are used in this document.

Document Creation Date

March 2004

Document Revision Date

March 2004

Document Review Date

March 2004

Document URL

http://nsidc.org/data/docs/daac/nsidc0194_ammr_wakasa.gd.html