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American Geophysical Union, Spring 1998 Meeting, Boston, Massachussetts, May 26-29, 1998
AN: H51C-08
TI: A Simple Water and Energy Balance Model for Remote Sensing Utilisation
AU: G Boulet
AF: 1
EM: ghani@cideson.mx
AU: *A Chehbouni
AF: 1
EM: ghani@cideson.mx
AU: I Braud
AF: 2
EM:
AF: (1) ORSTOM/IMADES, Reyes \& Aguascalientes Esq., Col. San
Benito
CT: Hermosillo
ST: Sonora
PC: C.P. 83190
CO: Mexico
AF: (2) LTHE
CT: Grenoble
ST:
PC:
CO: France
AB: In this study a simple Soil-Vegetation-Atmosphere Transfer (SVAT)
model will be presented. This study is being conducted as part of the
Semi-Arid Land-Surface-Atmosphere (SALSA) Program. The model is built
with a single bucket and single layer representation, with one bulk
surface of mixed vegetation and soil and a single soil reservoir.
Classical atmospheric forcing is imposed at reference level. It uses
the concepts of infiltration and evaporation capacities to describe
water infiltration and evaporation from a bucket of depth d
corresponding to the hydrologically active depth, i.e. the mean of the
average infiltration depth and the average evaporation depth. The
atmospheric forcing is divided into storm and interstorm periods, and
both evaporation and infiltration phenomena includes the well known
three stages representation: one at potential(ponding rate), one at a
rate set by the soil water content, and one at a zero rate if water
content reaches one of its range limits, namely saturation and
residual values. The simplicity of this model is suitable for the
investigation of the spatial variability of the mass and energy water
balance, and its one-layer parameterization allows a direct use of
remote sensing data.
SC: H
DE: 0315
DE: 1640
DE: 1833
MN: 1998 Spring Meeting
AN: H32G-01
TI: Status of the Semi-Arid Land-Surface-Atmosphere (SALSA) Program
AU: *A Chehbouni
AF: 1
EM: ghani@cideson.mx
AU: D C Goodrich
AF: 2
EM: goodrich@tucson.ars.ag.gov
AU: C Watts
AF: 1
EM:
AU: B Goff
AF: 2
EM:
AF: (1) ORSTOM/IMADES, Reyes \& Aguascalientes Esq., Col. San
Benito
CT: Hermosillo
ST: Sonora
PC: C.P. 83190
CO: MEXICO
AF: (2) USDA-ARS-SWRC, 2000 E. Allen Rd.
CT: Tucson
ST: Arizona
PC: 85719
CO: USA
AB: The goal of the SALSA program is to understand, model and predict the
consequences of natural and human-induced change on the basin-wide
water balance and ecological diversity of semiarid regions at event,
seasonal, interannual, and decadal time scales. This is a long term
program whose current research and integrated measurement efforts are
focused on the San Pedro River basin which originates in northern
Sonora, Mexico and flows north into southeastern Arizona. This is a
multidisciplinary that will attempt to determine the role of
vegetation, soils and climate, as well as human impacts on the
catchment-scale hydrologic response. This includes not only runoff
response but evapotranspiration. The objectives of this presentation
are: 1) To summarize and highlight the most significant results
obtained during the 1997 field campaign; 2) To present our objectives
for the 1998 field season and to describe the experimental design to
address them; and, 3) To discuss methods of analyzing and integrating
a wide variety of research and measurements.
SC: H
DE: 1836
DE: 1818
DE: 1640
MN: 1998 Spring Meeting
AN: H51C-09
TI: Examination of View Angle Effects on Surface Temperature Measurements
Over Semi-Arid Grassland
AU: *A Chehbouni
AF: 1
EM: ghani@cideson.mx
AU: Y H Kerr
AF: 2
EM:
AU: G Boulet
AF: 1
EM:
AU: C Watts
AF: 1
EM:
AU: J S Rodriguez
AF:
EM:
AU: D C Goodrich
AF: 3
EM:
AF: (1) ORSTOM/IMADES, Reyes \& Aguascalientes Esq., Col. San
Benito
CT: Hermosillo
ST: Sonora
PC: C.P. 83190
CO: MEXICO
AF: (2) CESBIO
CT: Toulouse
ST:
PC:
CO: France
AF: (3) USDA-ARS-SWRC
CT: Tucson
ST: Arizona
PC: 85719
CO: USA
AB: It is now well established that both reflected and emitted radiation
from most natural surfaces exhibit substantial departure from
lambertian behavior. In contrast to the visible and near-infrared
spectral part of the spectrum, view angle effects on thermal infrared
bands have not been well documented. This is of importance in arid and
semi-arid regions where no single surface component totally dominates
the exchange of water and heat with the atmosphere and therefore the
surface temperature which represents the result of the equilibrium of
the surface. The objective of this analysis is to examine the effects
of view angle on radiative surface measurements over semi-arid
grassland in the San Pedro basin in the context of the Semi-Arid
Land-Surface-Atmosphere (SALSA) Program. Data collected using two
infrared radiometers aiming at the same spot with the nadir and 45
degree view angles are used. The difference between nadir and of nadir
measurements are examined with respect to vegetation status and
dynamic, surface soil moisture and the overall all atmospheric
conditions.
SC: H
DE: 1640
DE: 3322
DE: 3359
MN: 1998 Spring Meeting
AN: H51C-10
TI: In-Situ and Remote Measurements to Estimate Riparian
Evapotranspiration as part of the SALSA Program
AU: D C Goodrich
AF: 1
EM: goodrich@tucson.ars.ag.gov
AU: *A Chehbouni
AF: 2
EM: ghani@cideson.mx
AU: T Maddock, III
AF: 3
EM:
AU: R Mac Nish
AF: 3
EM:
AU: M S Moran
AF: 4
EM:
AU: D A Williams
AF: 8
EM:
AU: D I Cooper
AF: 5
EM:
AU: L E Hipps
AF: 6
EM:
AU: J Schieldge
AF: 7
EM:
AU: J Qi
AF: 4
EM:
AU: B Goff
AF: 1
EM:
AF: (1) USDA-ARS-SWRC, 2000 E. Allen Rd.
CT: Tucson
ST: AZ
PC: 85719
CO: USA
AF: (2) ORSTOM/IMADES
CT: Hermosillo
ST: Sonora
PC:
CO: Mexico
AF: (3) Univ. of Arizona, HWR
CT: Tucson
ST: AZ
PC: 85721
CO: USA
AF: (4) USDA-ARS-USWCL
CT: Tucson
ST: AZ
PC: 85719
CO: USA
AF: (5) LANL
CT: Los Alamos
ST: NM
PC: 87545
CO: USA
AF: (6) Utah St. Univ.
CT: Logan
ST: UT
PC: 84322
CO: USA
AF: (7) JPL
CT: Pasadena
ST: CA
PC: 91109
CO: USA
AF: (8) Univ. of Arizona, RNR
CT: Tucson
ST: AZ
PC: 85721
CO: USA
AB: Riparian regions often harbor a disproportionate amount of
biodiversity in arid and semi-arid regions due to the presence of
perennial water. Evapotranspiration from these riparian areas can also
be a significant portion of the overall basin water balance, yet it is
very difficult to estimate over a large area. Better understanding and
quantification of annual, large-area riparian ET is one of the primary
1997 objectives of the Semi-Arid LandSurface-Atmosphere (SALSA)
Program. To effectively estimate riparian ET over a large area will
require the use of remote sensing techniques. A number of
multidiscipilinary experimental field campaigns utilizing both remote
and in-situ measurements were conducted in the U.S. portion of the
Upper San Pedro Basin riparian system to address this objective during
the 1997 growing season. Methods included simultaneous measurements of
streamflow, regional and alluvial groundwater levels, vadose zone soil
moisture, ET by micrometeorology, sap flow, and LIDAR techniques, and
isotopes to define water sources for the riparian forest. Simultaneous
ground, aircraft and satellite measurements were made to enable remote
estimation of riparian ET to define this critical boundary condition
for regional groundwater modeling.
SC: H
DE: 1640
DE: 1818
DE: 1836
MN: 1998 Spring Meeting
AN: H51C-11
TI: Tracking Soil Moisture Content in Semi-Arid Environments: Use of a
Combined Synthetic Aperture Radar (SAR) and Optical Remote Sensing
Technique
AU: M. S. Moran
AF: 1
EM: moran@tucson.ars.ag.gov
AU: D. C. Hymer
AF: 1
EM: dhymer@tucson.ars.ag.gov
AU: Jiaguo Qi
AF: 1
EM: qi@tucson.ars.ag.gov
AU: D. C. Goodrich
AF: 2
EM: goodrich@tucson.ars.ag.gov
AU: *A. Chehbouni
AF: 3
EM: Ghani@cideson.mx
AF: (1) USDA-ARS US Water Conservation Laboratory, 2000 E. Allen
Rd.
CT: Tucson
ST: AZ
PC: 85719
CO: USA
AF: (2) USDA-ARS Southwest Watershed Research Center, 2000 E. Allen
Rd.
CT: Tucson
ST: AZ
PC: 85719
CO: USA
AF: (3) ORSTOM/IMADES, Reyes y Aguacalientes, Col. San
Benito
CT: Hermosillo
ST: Sonora
PC:
CO: Mexico
AB: The spatial distribution of soil moisture influences a variety of
hydrological and ecological processes within a river basin. Previous
experiments have shown the utility of using satellite-based Synthetic
Aperture Radar (SAR) supplemented by optical remote sensing data to
periodically assess regional surface soil moisture content. In this
study, we examine the feasibility of using the SAR/optical technique,
in conjunction with a soil-vegetation-atmosphere transfer (SVAT)
model, to predict and track soil moisture over time at several sites
within the Upper San Pedro River basin in southeastern Arizona, USA.
The work is being conducted as part of the Semi-Arid
Land-Surface-Atmosphere ("SALSA") Program, and will contribute to the
monitoring and prediction objectives of the program. In the experiment
conducted thus far, surface soil moisture and vegetation conditions at
each study site were measured several times throughout the year,
concurrent with ERS-2 SAR and Landsat TM satellite overpasses. Initial
analysis shows that the SAR data, corrected for surface roughness and
standing biomass using the optical data, were reasonably correlated
with surface soil moisture content at the study sites. This
information, along with continuous, soil-profile moisture data
collected at related sites, will be used to test the predictive
capabilities of a SVAT model initialized and updated with surface soil
moisture data derived from satellite imagery.
SC: H
DE: 1866
DE: 1640
DE: 1694
MN: 1998 Spring Meeting
AN: H42F-06
TI: Soil Moisture and Plant Relations in the Semiarid Southwest
AU: *R L Scott
AF: 1
EM: russell@hwr.arizona.edu
AU: T O Keefer
AF: 2
EM:
AU: W J Shuttleworth
AF: 1
EM:
AU: D C Goodrich
AF: 2
EM:
AF: (1) Department of Hydrology and Water Resources, University of
Arizona
CT: Tucson
ST: AZ
PC: 85721
CO: USA
AF: (2) Southwest Watershed Research Center, USDA-ARS, 2000 E. Allen
Road
CT: Tucson
ST: AZ
PC: 85719
CO: USA
AB: This study begins with the examination of the water use for two
dominant riparian plant species in the Southwest. Using observations
of the surface energy balance, Bowen ratio, we determine the
evapotranspiration from a perennial flood plain bunch-grass
(Sporobolus Wrightii) and a mesquite-dominated (Prosopus Spp.)
community over the course of several seasons. This water use is then
compared with records of precipitation and vertical soil moisture
profiles to determine the dominant controls on the plants' water use.
We find that the grass, though deep rooted, relied primarily upon
water from recent precipitation stored in the shallow, near-surface
soil profile (0 - .1 meters depth). For the mesquite, transpiration
was not strongly linked to recent precipitation input nor near-surface
soil moisture (0 - 2 meters depth). Next, we examine the possibility
that the mesquite, along with other deep-rooted shrubs in the area,
rely upon water deep in the soil column that infiltrates to depth
primarily in the winter season when the vegetation is senescent. To do
this, we use observations from a 7-year record of soil moisture which
indicates that significant infiltration beyond .5 meters depth occurs
only during wetter-than-normal winters. These observations along with
meteorological information are incorporated into a model of the vadose
zone to determine relative rates of near-surface versus deep soil
moisture replenishment that occurs over a multi-year time
span.
SC: H
DE: 1875
DE: 1818
DE: 1866
MN: 1998 Spring Meeting
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