The three major objectives of the project are outlined: (1) to describe atmospheric water vapor features as functions of space and time; (2) to evaluate remotely sensed measurements of water vapor content; and (3) to study relations between fine-scale water vapor fields and convective activity. Data from several remote sensors were used. The studies used the GOES/VAS, HIS, and MAMS instruments have provided a progressively finer scale view of water vapor features

Fuelberg, Henry E.

English

NASA Technical Reports Server

N91-32682
REMOTE SENSING OF WATER VAPOR FEATURES
Henry E. Fuelberg
Department of Meteorology
Florida State University
Tallahassee, FL 32306
(904) 644-6466 Voice
(904) 644-9642 FAX
Recent Accomplishments
Our current research has three major objectives:
1) Describe atmospheric water vapor features as functions of space and time,
2) Evaluate remotely sensed measurements of water vapor content, and
3) Investigate relations between f'me-scale water vapor fields and convective activity.
We have been utilizing data from several remote sensors as part of this research. Our
investigations utilizing the GOES/VAS, HIS, and MAMS instruments have provided a progressively
timer scale view of water vapor features. Recent efforts have been focused in several areas:
1) VAS Evaluations--Error characteristics of VAS soundings have been examined. Olson
(1990), Olson and Fuelberg (1990), and Fuelberg and Olson (1991) calculated agreements between VAS
operational retrievals and radiosonde soundings, and between both versions of derived thermodynamic
variables. Breidenbach (1990) and Breidenbach and Fuelberg (1990) evaluated time tendencies of VAS
sounding variables. Each of these studies showed that VAS operational retrievals have serious
deficiencies in sensing water vapor. Nonetheless, VAS products still can be used advantageously in
some applications if special computational procedures are employed beyond those utilized operationally.
2) Simulated imagery--Muller and Fuelberg (1990) created simulated VAS 6.7 micron imagery
by utilizing numerically predicted soundings from the LAMPS model as input to radiative transfer code.
By comparing the simulated imagery to LAMPS' mass, moisture, and momentum fields, it was possible
to better understand how the atmosphere produced the bands and swirls that were evident in the water
vapor imagery. Brad Muller now is applying this methodology to the AMSU instrument. His current
work is being sponsored by a NASA Graduate Student Researchers Program which allows him to work
closely with Dr. Franklin Robertson and other scientists at NASA/Marshall.
3) VAS Case Stu.dies and Algorithm Development--Fuelberg et al. (1991) used VAS retrievals
to understand an event of sudden surface drying over central Tennessee during the summer. The VAS
soundings used here were not the operational versions whose limitations were described above, but a
special "research quality" data set that was prepared later. Results indicated that surface based mixing
65
https://ntrs.nasa.gov/search.jsp?R=19910023368 2020-03-17T15:03:09+00:00Z
penetratedanarrowdry tonguealoft. Intensethunderstormsformedalongtheperipheryof thesurface
dry area.
Former graduate student Anthony Guillory has worked with Dr. Gary Jedlovec of MSFC to
apply to VAS data Jedlovec's split window technique for calculating precipitable water. This algorithm
is simpler and faster than many others, and it has produced very encouraging results (Guillory, 1991).
Guillory was sponsored by a NASA Graduate Student Researchers Program--Minority Focus.
4) HIS Studies--Bradshaw and Fuelberg (1990) and Bradshaw (1991) have evaluated HIS
interferometer retrievals prepared by scientists at the University of Wisconsin. Our efforts were an
independent examination of the Wisconsin products. Specifically, HIS sounding data were compared
against those from radiosondes, VAS, and MAMS; and the HIS retrievals were used to examine the
causes of mesoscale cloud patterns. Results suggest that HIS will be an improvement over current filter
wheel technology. However, since only two cases were investigated, additional studies are needed to
fully explore HIS capabilities in diagnosing small scale water vapor features. The CAPE project offers
this possibility.
Current Focus
Three research projects currently are in progress. The AMSU efforts of Brad Muller were
described above. In addition, graduate student Mike Nichols is exploring a summer case over northern
Alabama when MAMS indicated distinctive cumulus cloud patterns that appear to be related to
topography and mesoscale circulations along the Tennessee River. To explore causes for the cloud
features, precipitable water and skin temperatures are being calculated from MAMS imagery. In
addition, a boundary layer model is being used to estimate growth of the mixed layer during the
daytime.
A second MAMS study, by graduate student Rick Knabb, is utilizing MAMS data from a Pre-
CAPE flight over Florida during October 1990. This case is characterized by strong north-south
moisture gradients as well as outflow boundaries from previous thunderstorms. MAMS-derived thermal
and moisture products are being used to explain cloud pattems during and after the MAMS flight.
Plans for 1992
The first objective is to complete the AMSU activities and the two ongoing projects involving
MAMS. Conference papers and journal manuscripts describing findings will be prepared. As a second
objective, we would like to draw on the experience we have gained with MAMS and HIS, by
performing CAPE related investigations that utilize these data sources. Florida has an abundance of
small scale circulations during the summer that can trigger convective activity (e.g., land/sea breezes,
river/swamp/lake breezes, and outflows from previous thunderstorms). Our experience suggests that
mesoscale water vapor and stability features also are present. Data collected during CAPE would be
ideal for studying the capabilities of MAMS, HIS, and VAS for detecting these features and learning
how they relate to thunderstorm formation. We will prepare a proposal for conducting this type of
research.
66
Our secondmajorresearchactivitywill investigatethenewseriesof GOESsatellites(GOES
l-M) thatwill be launchedby Spring1993. GOESI-M will besuperiorto thecurrentVAS system,
especiallyin regardto moisturesensing.Thesenewsatelliteswill betheonlygeostationaryplatforms
for moisturemappingfor theremainderof thisdecade,andpossiblyfor thenext 15years. Sincea
betterunderstandingof atmosphericwatervaporis thegoalof amajornewNASA researchinitiative
calledGVaP,our researchwill develop,evaluate,anduseGOESI-M productsin hydrologicstudies,
therebypermittingimmediateprogresstowardthegoalsof GVaP.
Our objectivesfor theGOESI-M researchareto:
1)Understandfeaturesin GOESI-M watervaporimageryandtheirrelationshipsto horizontal
andverticalhumiditydistributionsandvariouskinematic/dynamicprocesses.
2) Quantifytheaccuracy,representativeness,andinformationcontentof GOESI-M imagery
andproductsfrom thatimagery,includingtemperature/dewpointprofiles,variousmeasuresof water
vaporcontentandwatervaportrackedwinds.
3)Developnewproceduresfor examiningatmosphericwatervaporthattakeadvantageof the
enhancedcapabilitiesof GOESI-M productsoverthosenow availablefromVAS.
4) As a resultof the above,further thegoal of improvingourunderstandingof therole of
atmosphericwatervapor.
Theproposedresearchwill conductedjointly with Dr. GaryJedlovecandotherscientistsat
NASA/MarshallSpaceFlightCenter.JedlovecandFuelberghavesubmittedajoint proposalto NASA
Headquartersdescribingdetailsof theresearch.Briefly stated,bothobservedimageryandsimulated
imagerypreparedfromanumericalpredictionmodelandradiativetransfercodewill beemployed.The
useof simulatedimagery will allow considerable research to be conducted prior to the launch of GOES
I so that some findings will be available when the new satellite becomes operational.
Publications
Bradshaw, J. T., 1991: High resolution intefferometer sounder (HIS) analyses of mesoscale phenomena.
M. S. Thesis, Florida State University, Tallahassee, 146 pp.
Bradshaw, J. T., and H. E. Fuelberg, 1990: HIS analyses of mesoscale phenomena.
Conf. Satellite Meteor. and Ocean. London, Amer. Meteor. Soc., 329-333.
Breidenbach, J. P., 1990: Time trends of VAS satellite-derived soundings. M. S. Thesis, Florida State
University, Tallahassee, 46 pp.
Breidenbach, J. P., and H. E. Fuelberg, 1990: Time trends of VAS satellite-derived soundings.
Preprints, 5th Conf. Satellite Meteor. and Ocean. London, Amer. Meteor. Soc., 360-365.
67
Fuelberg,H. E.,andS.R. Olson,1991: Assessmentof VAS-derived retrievals and parameters used
in thunderstorm forecasting. Mon. Wea. Rev., 119, 795-814.
Fuelberg, H. E., R. Schudalla, and A. Guillory, 1991: Mesoscale analysis of a pre-convective
environment. Mon. Wea. Rev., 119, 1391-1406.
Guillory, A., 1991: A physical split window technique for deriving precipitable water utilizing VAS
data. M. S. Thesis, Florida State University, Tallahassee, 70 pp.
Muller, B. M., and H. E. Fuelberg, 1990: A simulation and diagnostic study of water vapor image dry
bands. Mon. Wea. Rev., 118, 705-722.
Olson, S.R., 1990: An evaluation of VAS-derived parameters commonly used in thunderstorm
forecasting. M. S. Thesis, Florida State University, Tallahassee, 70 pp.
Olson, S. R., and H. E. Fuelberg, 1990: An evaluation of VAS-derived severe storm parameters.
Preprints, 16th Conf. Severe Local Storms, Kananaskis Park, Canada, Amer. Meteor. Soc., 150-
153.
68


Remote sensing of water vapor features

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server