MOPITT Campaign

2 March 1998 - 6 March 1998

Lead Scientist: Jinxue Wang

Observatory: sgp, sgp

It is important to have confidence in the correlative data and associated data processing algorithms before they can be used to validate the MOPITT data products. It is also useful to test the intercomparison techniques which are to be used in post-launch MOPITT data validation. The Pre-launch MOPITT Validation Exercise (Pre-MOVE) was a validation campaign at the Southern Great Plain (SGP) Cloud and Radiation Testbed (CART) of the Department of Energy Atmospheric Radiation Measurement (DOE/ARM) program in Lamont, Oklahoma from March 2 to March 6 of 1998. The reasons for conducting Pre-MOVE at the CART site included the following: (1) It is a heavily instrumented site resulting in good characterization of surface and the atmosphere column; (2) We can make use of CART high resolution solar absorption interferometer (SORTI & ASTI), thermal emission interferometer (AERI), lidars, and radiosonde data. This saves us from deploying similar instruments ourselves for Pre-MOVE; (3) There is excellent logistic support at the site.

The primary goals of Pre-MOVE included:

(1) Conduct a test of the MOPITT Airborne Test Radiometer (MATR) and associated data processing algorithm by comparing the retrieved CO profiles from MATR observations with aircraft in-situ CO profile measurement by the NOAA/CMDL flask system.

(2) Validate the retrieval algorithm, which derives column CO from ground-based thermal emission interferometer (AERI) measurement, to be used by McMillan et al. for post-launch MOPITT data validation. The retrieved CO column will be compared with that derived from aircraft in-situ CO profile measurement by the NOAA/CMDL flask system and other techniques.

(3) Validate the retrieval algorithm, which derives column CO and possibly tropospheric CO profile from ground-based solar absorption interferometer (SORTI) measurement to be used by Frank Murcray et al. and Pougatchev et al. for MOPITT validation. The retrieved CO column will be compared with that derived from aircraft in-situ CO profile measurement by the NOAA/CMDL flask system and other techniques.

(4) Validate the retrieval algorithm, which derives column CO and possibly tropospheric CO profile from ground-based solar absorption interferometer (SORTI) measurement, to be used by Murcray et al. and Pougatchev et al. for MOPITT validation. The retrieved CO column will be compared with that derived from aircraft in-situ CO profile measurement by the NOAA/CMDL flask system and other techniques. Two independent algorithms, one by Murcray et al. and one by Pougatchev et al., will be used and compared in the retrieval of columns of CO and CH4 and possibly CO profiles from high resolution solar absorption measurements by Fourier transform interferometers. This will give us more confidence in the use of the large number of observations by Fourier transform interferometers around the world. The involvement of both groups give us the desired global coverage by ground-based Fourier transform interferometers and grating spectrometers.

(5) Validate the retrieval algorithm, which derives total CO column from ground-based grating spectrometer measurement, to be used by Yurganov and Tolton for MOPITT data validation. Similar grating spectrometers have been used in Russia, China, and possibly other countries for many years to monitor total CO column. The validation of those kind of measurements as part of the Pre-MOVE will give us confidence to use similar measurements in Russia and China for MOPITT data validation.

(6) Intercompare all the instruments and techniques to be used in post-launch MOPITT data validation. It is expected that those intercomparisons will lead to the refinement of all the associated data processing algorithms and intercomparison protocols.

Activity Summary

All instruments or instrument types to be used for post-launch MOPITT data validation were part of the Pre-MOVE from March 2 to March 6, 1998 at the CART site. Each instrument and its measurement during Pre-MOVE are described below:

(1) MOPITT Airborne Test Radiometer (MATR) from NCAR. MATR was fitted onto the Citation aircraft from Department of Energy Remote Sensing Laboratory in Las Vegas. The Citation was stationed at the Jefferson county airport in Colorado. MATR flew over the CART site at ~ 39,000 ft. for about 2 hours on March 2, March 3, and March 6, 1998.

(a). On 2 March 1998, times of closest approaches to teh CART site are: 16.02312, 16.22924, 16.61062, 16.68979, 17.35118, 17.44257, 17.97924 hour GMT. The overall flight area covers the latitude range of 36.2 degree to 37.4 degree, and longitude range of -97 degree to -98 degree.

(b). On 3 March 1998, times of closest approaches to teh CART site are: 16.10785, 16.48618, 16.79701, 17.10257, 17.36646, 17.69535, 17.95715 hour GMT. The overall flight area covers the latitude range of 36.2 degree to 37.1 degree, and longitude range of -96.5 degree to -98.5 degree.

(c). On 6 March 1998, times of closest approaches to teh CART site are: 16.80354, 17.10229, 17.37729 hour GMT. The overall flight area covers the latitude range of 36.0 degree to 37.4 degree, and longitude range of -97.2 degree to -97.8 degree.

(2) Automated flask sampling system from NOAA/CMDL. The NOAA/CMDL automated flask system was carried by a chartered Piper Seneca 4 Turbocharged Piston Twin from Cox Aviation, Inc. in Wichita, Kansas. The basic flight profile for the chartered small aircraft is to ascend from ground to about 30,000 ft, then descend from 30,000 ft to ground and take a set of air samples at a interval of approximately 0.5 km. The samples are analyzed at the NOAA/CMDL laboratory in Boulder, CO. Flask problems prevented carrying out planned sampling on 2-3 March 1998. Two successful set profiles for CO, CH4, CO2 were obtained on 6 March 1998 from 3000 to 26,000 ft. (~ 1km to 8km) at a vertical resolution of ~0.3 km. The CO, CH4 and CO2 profiles for 6 March 1998 are available now to interested users. The CO2 mixing ratios may be of interest to researchers who are using CO2 band to retrieve atmospheric temperature profiles at CART site from AERI spectra.

(3) University of Toronto ground-based grating spectrometer. The grating spectrometer was shipped from University of Toronto to the CART site on February 27, 1998. Large number of solar absorption spectra were collected on 3 March 1998, which is the only clear day during the campaign. Limited number of spectra were obtained for the remaining days because of cloud cover.

(4) ARM ground-based solar absorption Fourier transform interferometer (SORTI). SORTI is an ARM instrument. Based on current CART site operation plan, measurements by SORTI are being conducted and archived by the ARM program every day.

(5) ARM ground-based thermal emission Fourier transform interferometer (AERI). Based on current CART site operation plan, measurements by AERI are being conducted and archived by the ARM program every day.

(6) Meteorological data by radiosondes. Based on the current CART operation plan, radiosondes launches are conducted three times a day at 7:00 AM, 12:00 noon and 6:00 PM local time. Because most of the Pre-MOVE measurements were conducted around 10:00 AM local time. One extra radiosonde launch was made each day from March 2 to March 6, 1998 to support Pre-MOVE.

Timeline

Campaign Data Sets

IOP Participant Data Source Name Final Data
Jinxue Wang MOPITT Airborne Test Radiometer Order Data