TCSP ER-2 Microwave Temperature Profiler (MTP)
Table of Contents
Introduction
The Tropical Cloud Systems and Processes (TCSP) mission was conducted by NASA and the National Oceanic and Atmospheric Administration (NOAA) in Costa Rica throughout the month of July, 2005. The goal of this mission was to help us better understand how hurricanes and other tropical storms are formed and intensify.
The Microwave Temperature Profiler (MTP), mounted on the right engine cheek of a NASA ER-2 research aircraft, collected these data during the TCSP field experiment. The ER-2 was used to overfly storms at high altitude.
The MTP retrieves profiles of air temperature versus altitude along an aircraft flight track. It does this by measuring the natural thermal microwave emission from oxygen molecules in the earth’s atmosphere, and then performing a statistical retrieval inversion procedure. This retrieval is based on an archive of thousands of atmospheric soundings that results in the most likely temperature profile given the measurements.
Instrument Description
The airborne MTP instrument is a passive microwave radiometer that measures thermal emission from oxygen molecules along the viewing direction. A stepper motor rotates a 45-degree shaped reflector so that radiation entering a receiving horn is sequenced through a set of 10 elevation angles, ranging from -58.2 to +60.0 degrees (within a vertical plane that is offset 20 degrees in azimuth from the direction of flight). At each viewing position a local oscillator is sequenced through two frequencies: 56.66 and 58.80 GHz. Each 14-second observing cycle produces a set of 20 brightness temperatures, which are converted by a linear retrieval algorithm to a profile of air temperature versus altitude. Altitude coverage is 15 to 25 km while flying at 19 km. T(z) profiles are obtained every 2.9 km along the flight path.
Much more detailed information about the instrument can be obtained from the Jet Propulsion Laboratory, California Institute of Technology, the instrument owner. They have an outstanding web site located at http://mtp.jpl.nasa.gov/ . This site has a link to an excellent tutorial, A Layperson's Guide to Remote Temperature Sounding.
Data Products and Format
The ASCII data file naming convention is:
TCSP_MTP_yyyymmdd_MP.txt
where TCSP identifies the field mission, MTP identifies the instrument, yyyymmdd is the four digit year, month, and "day of month", MP identifies that the data is from the microwave profiler, and txt shows that these data are in ASCII format (Gaines-Hipskind). The data files have a large descriptive header, which describes in detail the format of the data which follows. An example is shown below:
62 2110
MJ MAHONEY (Michael.J.Mahoney@jpl.nasa.gov)
M/S 246-102; Jet Propulsion Laboratory; Pasadena, CA 91109-8099
ER-2 Microwave Temperature Profiler (MTP/ER2)
TCSP
1 1
2005 06 18 2006 03 16 20050001 {FLT DATE, REDUCTION DATE & FLIGHT NUMBER}
0.0 0.0
Remote sensing altitude (meters)
Elapsed UT seconds from 0 hours on day given by DATE
4 {NV = number of primary variables: temp, SEtemp, Zg, #density}
1.0 1.0 1.0 1E+21 {scale factors for primary variables: temp, SEtemp, Zg, #densit y}
99999 9999 99999 99999 {missing values for primary variables: temp, SEtemp, Zg, #densi ty}
Retrieved air temperature (K)
Standard error of retrieved air temperture (K)
Geometric altitude (meters).
Molecular air density (number per cubic meter)
13 {number of auxiliary variables}
1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0
99 99.999 99.9 99.9 999.9 99.9 99.9 999.9 999.9 99.999 999.999 999.9 9.99
NX(1) is the number of altitudes in subsequent data records
Pressure altitude of ER-2 (km)
Aircraft pitch (deg)
Aircraft roll (deg)
Horizon brightness temperature (ie, OAT, similar to SAT); avg ch1 & ch2(K)
Tropopause #1 (km).
Tropopause #2 (km).
Potential temperature of tropopause #1 (K).
Potential temperature of tropopause #2 (K).
Latitude (deg)
Longitude (deg)
dT/dz (K/km) for 1.0 km layer centered on aircraft flight altitude.
MRI (-) a retrieval quality metric
8 {number of special comment lines}
*** FINAL DATA FINAL DATA FINAL DATA FINAL DATA FINAL DATA FINAL DATA FINAL DATA
***
*** Users of this data are strongly encouraged to discuss their use with the PI
***
*** More information at URL: http://mtp.jpl.nasa.gov/missions/tcsp/tcsp.html
***
***
*** FINAL DATA FINAL DATA FINAL DATA FINAL DATA FINAL DATA FINAL DATA FINAL DATA
19 {number of normally included comment lines}
Here's a brief tutorial on how to decipher the MTP data: Data groups
consist of the following group of lines per 15-second observing cycle.
First line is: UTSEC, number of retrieval levels in following table, Pressure
Altitude, Pitch, Roll, Outside air temp (K), tropopause altitude #1 (km),
tropopause altitude #2 (km) [if present], potential temperatures of tropopause
#1 and #2, latitude, longitude, lapse rate near flight level, & a retrieval quality me tric..
The 1-liners (for each cycle) can be stripped & imported into a spreadsheet
for convenient plotting of trop altitude, lapse rate, etc. The tropopause
altitudes are calculated by cubic spline interpolation of the retrieved
altitudes using the WMO definition (that is, trop #1 is lowest altitude
where average lapse rate > -2 K/km from initial -2 K/km point to any point
within 2 km; trop #2 occurs above first trop after lapse rate is < -3K/km
for >1 km, and then first trop definition applies, possibly from within
the 1 km region.)
Remaining set of lines for each cycle consist of 5 columns: col#1 is pressure
altitude (meters), col#2 is temperature from MTP (Kelvin), col#3 is temperature
error estimate (K), col#4 is geometric altitude (meters), based on GPS
altitude (meters), and col#5 is molecular air density [1E+21/m3].
49564 0 0.692 3.9 -0.2 274.2 15.0 99.9 330.7 999.9 34.924 -117.885 5.6 2.00
49579 0 0.692 3.9 -0.2 274.2 15.1 99.9 332.4 999.9 34.924 -117.885 3.8 2.00
|
The browse images consist of a flight track image and a data image for each ER-2 flight. examples of the file names are shown below.
TZS_yyyymmdd.png
Track_yyyymmddER.png
where yyyymmdd is the year, 2 digit month, and "day of month". These image files may be viewed with almost any image viewer and samples appear below:
References
Ling Wang, M. Joan Alexander, Thaopaul V. Bui, and Michael J. Mahoney, Small-Scale Gravity Waves in ER-2 MMS/MTP Wind and Temperature Measurements during CRYSTAL-FACE, to be submitted to Atmos. Chem. Phys, September 2005.
Christina L. Smith, John W. Nielsen-Gammon, M.J. Mahoney, Wayne Angevine, Carl Berkowitz, Christof Senff, Allen White, Christopher Doran, and Kevin Knupp, An intercomparison of mixing height estimates using radiosonde, radar wind profilers, airborne aerosol backscatter lidar, and airborne microwave temperature profiler, to be submitted to JGR-Atmospheres, September 2005.
P. J. Popp, T. P. Marcy, E. J. Jensen, B. Karcher, D. W. Fahey, R. S. Gao, T. L. Thompson, K. Rosenlof, E. C. Richard, R. L. Herman, E. M. Weinstock, J. B. Smith, R. D. May, J. C. Wilson, A. J. Heymsfield, M. J. Mahoney, and A. M. Thompson, The observation of nitric-acid containing particles in the tropical lower stratosphere, to be submitted to Science.
Jasna V. Pittman, Elliot M. Weinstock, David S. Sayres, Jessica B. Smith, James G. Anderson, Owen R. Cooper, Steven C. Wofsy, Irene Xueref, Cristof Gerbig, Bruce C. Daube, Erik C. Richard, Brian A. Ridley, Andrew Weinheimer, Max Lowenstein, Hans-Jurg Jost, Jimena P. Lopez, Michael J. Mahoney, and Thomas L. Thompson, Identifying transport pathways into the subtropical lowermost stratosphere during the summertime, to be submitted to JGR.
D. Lowe, A. R. MacKenzie, H. Schlager, C. Voigt, A. Dornbrack, M. J. Mahoney, and F. Cairo, Liquid Particle Composition and Heterogeneous Reactions in a Mountain Wave Polar Stratospheric Cloud, submitted to Atmos. Chem. Phys. (Discuss.)
B. Gamblin, O.B. Toon, Y. Kondo, N. Takegawa, H. Irie, M. Koike, P. K. Hudson, M. A. Tolbert, J. O. Ballenthin, D. E. Hunton, T. M. Miller, A. A. Viggiano, B. E. Anderson, M. Avery, G. W. Sachse, K. Guenther, C. Sorenson, M. J. Mahoney, Non-HNO3 Constituent of Noy Condensing on Low Temperature Upper Tropospheric Cirrus Cloud Particles, to be submitted to JGR May 2004.
T. P. Marcy, D.W. Fahey, R. S. Gao, P.J. Popp, E. C. Richard, T. L. Thompson, K. H. Rosenlof, E. A. Ray, R. J. Salawitch, B. A. Ridley, M. Lowenstein, J. C. Wilson, E. M. Weinstock, M. J. Mahoney, R. L. Herman, Quantifying Stratospheric Ozone in the Upper Troposphere Using in situ Measurements of HCl, Science, 9 April 2004: 261-265. (PDF File of paper: 0.8 MB)
Tomoko Kojima, Peter R. Buseck, James C. Wilson, J. Michael Reeves, and Michael J. Mahoney, Aerosol particles from tropical convective systems: 1. Cloud tops and cirrus anvils, J. Geophys. Res., 109, D12201, doi:1029/2004JD004504.
L. L. Pan, W. J. Randel, E. Browell, B. G. Gary, M. J. Mahoney, and E. J. Hintsa, Definitions and sharpness of the extratropical tropopause: A trace gas perspective, J. Geophys. Res., 109, D23103, doi:10.1029/2004JD004982.
B. Ridley, L.Ott, K. Pickering, L. Emmons, D.Montzka, A. Weinheimer, D. Knapp, F. Grahek, L. Li, G. Heymsfield, M. McGill, P. Kuecera, M. J. Mahoney, G. Brasseur, Florida thunderstorms: A faucet of reactive nitrogen to the upper troposphere, J. Geophys. Res., 109, D17305, doi:10.1029/2004JD004769.
P. J. Popp, R. S. Gao, T. P. Marcy, D. W. Fahey, P. K. Hudson, T. L. Thompson, B. Karcher, B. A. Ridley, A. J. Weinheimer, D. J. Knapp, D. D. Montzka, D. Baumgardner, T. J. Garrett, E. M. Weinstock, S. Dhaniyala, T. P. Bui, M. J. Mahoney, Nitric Acid Uptake, on Subtropical Cirrus Cloud Particles, J. Geophys. Res., 109, D06302, doi:10.1029/2003JD004255.
B. Ridley, E. Atlas, H. Selkirk, L. Pfister, D. Montzka, S. Donnelly, V. Stroud, E. Richard, K. Kelly, A. Tuck, T. Thompson, C. Brock, C. Wilson, D. Baumgardner, M. Mahoney, R. Herman, R. Freidl, J. Elkins, F. Moore, M. Ross, D. Anderson, Convective transport of reactive constituents to the tropical and mid-latitude tropopause region: I. Observations, Atmos. Environ., 38, 1259-1274, 2004.
Contact Information
To order these data or for further information, please contact:
Global Hydrology Resource Center
User Services
320 Sparkman Drive
Huntsville, AL 35805
Phone: 256-961-7932
E-mail: support-ghrc@earthdata.nasa.gov
Web: http://ghrc.nsstc.nasa.gov/
|
