Research & Grants
Journal Articles
Song, J ., Wesely, M.L., Holdridge, D.J., and Cook, D.R., 2006: Estimating the Long-term Hydrological Budget over Heterogeneous Surfaces. Journal of Hydrometeorology , Vol. 7, No. 1, 203214. Abstract
Shankman, D., Keim, B. and Song, J ., 2006: Flood frequency in China 's Poyan lake region: trends and teleconnections. International Journal of Climatology , 26: 1255-1266. Abstract
Song, J ., Liao, K., Coulter, R.L., and Lesht B.M., 2005: Climatology of the low-level jet at the southern Great Plains Atmospheric Boundary Layer Experiments site. Journal of Applied Meteorology, Vol. 44, No. 10, 15931606. Abstract
Miller, N.L., A. W. King, M. A. Miller, E. P. Springer, M. L. Wesely, K. E. Bashford and M. E. Conrad, K. Costigan, P. N. Foster, H. K. Gibbs, J. Jin, J. Klazura and B. M. Lesht, M. V. Machavaram, F. Pan, J. Song , D. Troyan, R. A. Washington-Allen, 2005: The DOE Water Cycle Pilot Study. Bulletin of the American Meteorological Society , 86 , 359-374.
Grossman, R., Yates, D., LeMone, M., Wesely, M.L., and Song, J ., 2005: Observed effects of horizontal surface temperature variations on the atmosphere over a Mid-west watershed during CASES 97. Journal of Geophysica l Research 110, No.6, D06117, doi:10.1029/2004JD004542
Lu, D. and J. Song, 2004, “A simplified atmospheric correction procedure for estimating surface temperature from AVHRR thermal data”, GIScience & Remote Sensing, 41:81-94
Song, J. 2003, "Radiation Measurements." book Chapter for "Phenology: An Integrative Environmental Science", edited by Mark D. Schwartz, October 2003, 592 pp. Book Series: TASKS FOR VEGETATION SCIENCE : Volume 39, Kluwer Academic Publishers, Dordrecht.
Song, J. and M.L. Wesely, 2003, "On comparison of modeled surface flux variations to aircraft observations". Agricultural and Forest Meteorology 117:159-171. Abstract
Song, J., D. Lu, M.L. Wesely, 2003, "On simplified atmospheric correction procedures for shortwave bands of satellite images", Photogrammetric Engineering and Remote Sensing 69, no. 5: 521-529. Abstract
M.L. Wesely, J. Song, R.T. McMillen, and T.P. Meyers, 2001, "Effects of soil moisture variation on deposition velocities above vegetation." Water, Air and Soil Pollution: Focus, 1, No. 5-6, 5-15. Abstract
Song J., M.L. Wesely,
R.L. Coulter, and E.A. Brandes, 2000, "Estimating watershed evapotranspiration
with PASS. Part I: inferring root-zone moisture conditions using satellite
data." Journal of Hydrometeorology, 1: 447-461. Abstract
Song J., M.L. Wesely, M.A. LeMone, and R.L. Grossman, 2000, "Estimating
watershed evapotranspiration with PASS. Part II: moisture budgets during drydown
periods." Journal of Hydrometeorology, 1: 462-473. Abstract
Song, J., 2000, "Changes in Dryness/wetness in China during the last
529 years." International Journal of Climatology, 20: 1003-1015.
Abstract
Song, J. and W. Gao, 1999, "An Improved Method to Derive Surface Albedo from Narrowband AVHRR Satellite Data: Narrowband to Broadband Conversion," Journal of Applied Meteorology, 38, 239-249.
Song, J., 1999, "Phenological
Influences on the Albedo of Prairie Grassland and Crop Fields." International
Journal of Biometeorology, 42, 153-157.
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PI, the U.S. Department of Energy, Climate Change Prediction Program 2004-2007, $196,435, The Role of Soil and Vegetation in the Future Climate. Summary
PI for "Long-term
surface hydrological study at Walnut River Watershed," (Project/Grant
G5A 63670) funded by the Department of Energy through Argonne National Laboratory,
duration is 05/15/2001 -05/15/2004. Summary
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Song, J ., Wesely, M.L., Holdridge, D.J., and Cook, D.R., 2006: Estimating the Long-term Hydrological Budget over Heterogeneous Surfaces. Journal of Hydrometeorology , Vol. 7, No. 1, 203214.
Abstract: Estimates of the hydrological budget in the Walnut River Watershed (WRW; ~5,000 km 2 ) of southern Kansas were made with a parameterized subgrid-scale surface (PASS) model for the period 19962002. With its subgrid-scale distribution scheme, the PASS model couples surface meteorological observations with satellite remote sensing data to update root-zone available moisture and to simulate surface evapotranspiration rates at high resolution over extended areas. The PASS model is observationally driven, making use of extensive parameterizations of surface properties and processes. Heterogeneities in surface conditions are spatially resolved to an extent determined primarily by the satellite data pixel size. The purpose of modeling the spatial and interannual variability of water budget components at the regional scale is to evaluate the PASS model's ability to bridge a large grid cell of a climate model with its subgrid-scale variation. Modeled results indicate that annual total evapotranspiration at the WRW is about 6688% of annual precipitation reasonable values for southeastern Kansas and that it varies spatially and temporally. Seasonal distribution of precipitation plays an important role in evapotranspiration estimates. Comparison of modeled runoff with stream gauge measurements demonstrated close agreement and verified the accuracy of modeled evapotranspiration at the regional scale. In situ measurements of energy fluxes compare favorably with the modeled values for corresponding grid cells, and measured surface soil moisture corresponds with modeled root-zone available moisture in terms of temporal variability despite very heterogeneous surface conditions. With its ability to couple remote sensing data with surface meteorology data and its computational efficiency, PASS is easily used for modeling surface hydrological components over an extended region and in real time. Thus, it can fill a gap in evaluations of climate model output using limited field observations.
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Abstract: Poyang Lake in Jiangxi Province is the largest freshwater lake in China and is historically a region of significant floods. Annual peak lake stage and the number of severe flood events have increased dramatically during the past few decades. This trend is related primarily to levee construction at the periphery of the lake that protects a large rural population. These levees reduce the area formerly available for floodwater storage resulting in higher lake stages during the summer flood season and catastrophic levee failures. Poyang Lake's most severe floods since 1950, and ranked from highest to lowest, occurred in 1998, 1995, 1954, 1983, 1992, 1973, and 1977. All of these floods occurred during or immediately following El Nino events, which are directly linked to rainfall in central China . The 2-year recurrence interval for maximum annual lake stage during El Nino years is 1.2 m higher than during non-El-Nino years. The 10-year recurrence interval is 1.4 m higher during El Nino years than during non El Nino years.
(Key Words: China , climate variability, flooding, El Nino-Southern Oscillation, Poyang Lake .)
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Abstract: We have used a unique data set obtained with combinations of minisodars and 915-MHz wind profilers at the Atmospheric Boundary Layer Experiments (ABLE) facility in Kansas to examine the detailed characteristics of the nocturnal low-level jet (LLJ). In contrast to instruments used in earlier studies, the ABLE instruments provide hourly, high-resolution vertical profiles of wind velocity from just above the surface to approximately 2 km above ground level (AGL). Furthermore, the 6-yr span of the data set allowed us to examine interannual variability in jet properties with improved statistical reliability. We found that LLJs occurred during 63% of the nighttime periods sampled. Although most of the observed jets were southerly, a substantial fraction (28%) was northerly. Wind maxima occurred most frequently at 200400 m AGL, though some jets were found as low as 50 m, and the strongest jets tended to occur above 300 m. Comparison of LLJ heights at three locations within the ABLE domain and at one location outside the domain suggests that the jet is equipotential rather than terrain following. The occurrence of southerly LLJ varied annually in a way that suggests a connection between the tendency for jet formation and the large-scale circulation patterns associated with El Niño and La Niña, as well as with the Pacific Decadal Oscillation. However, frequent and strong southerly jets that transport moisture downstream do not necessarily lead to more precipitation locally.
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Abstract: Evaluation of models of air-surface exchange is facilitated by an accurate match of areas simulated with those seen by micrometeorological flux measurements. Here, spatial variations in fluxes estimated with the parameterized subgrid-scale surface (PASS) flux model were compared to flux variations seen aboard aircraft above the Walnut River Watershed in Kansas. Despite interference by atmospheric eddies, the areas where the modeled sensible and latent heat fluxes were most highly correlated with the aircraft flux estimates were upwind of the flight segments. To assess whether applying a footprint function to the surface values would improve the model evaluation, a two-dimensional correlation distribution was used to identify the locations and relative importance of contributing modeled surface pixels upwind of each segment of the flight path. The agreement between modeled surface fluxes and aircraft measurements was improved when upwind fluxes were weighted with an optimized footprint parameter f, which can be estimated from wind profiler data and surface eddy covariance. Variations of the flight-observed flux were consistently greater than those modeled at the surface, perhaps because of the smoothing effect of using 1-km pixels in the model. In addition, limited flight legs prevented sufficient filtering of the effects of atmospheric convection, possibly accounting for some of the more prominent changes in fluxes measured along the flight paths.
Keywords: Footprint;
Eddy covariance; Aircraft, Land surface model; Latent heat flux; Sensible
heat flux
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Abstract:
Accurate corrections of Normalized Difference Vegetation Index (NDVI) for
atmospheric effects are currently based on modeling the physical behavior
of radiation as it passes through the atmosphere. An important requirement
for application of the physical models is detailed information on atmospheric
humidity and particles. Here, a method is described for making atmospheric
corrections without the need for detailed atmospheric observations. A simplified
approach for making atmospheric corrections to reflectances observed from
satellites is developed by using the unique spectral signature of water pixels
in satellite images. A radiative transfer model is applied to a variety of
clear-sky conditions to generate functional relationships between the radiation
due to the atmospheric scattering above water bodies and atmospheric radiative
properties. Test cases indicate that the resulting estimates of surface reflectances
and NDVI agree well with estimates made using a radiative transfer model applied
independently and with measurements made at the surface.
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Abstract:
The parameterized subgrid-scale surface flux (PASS) model provides a simplified
means of using remote sensing data from satellites and limited surface meteorological
information to estimate the influence of soil moisture on bulk canopy stomatal
resistance to the uptake of gases over extended areas. PASS-generated estimates
of bulk canopy stomatal resistance were used in a dry deposition module to
compute gas deposition velocities with a horizontal resolution of 200m for
approximately 5000 km2 of agricultural crops and rangeland. Results were compared
with measurements of O3 flux and concentrations made during April and May
1997 at two surface stations and from an aircraft. The trend in simulated
O3 deposition velocity during soil moisture drydown over a period of a few
days matched the trend observed at the two surface stations. For areas under
the aircraft flight paths, the variability in simulated O3 deposition velocity
was substantially smaller than the observed variability, while the averages
over tens of kilometers were usually in agreement within 0.1 cm/s. Model results
indicated that soil moisture can have a major role in deposition of O3 and
other substances strongly affected by canopy stomatal resistance. Keywords:
Dry deposition, latent heat flux, ozone, satellite observation, stomatal resistance.
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Abstract:
A model framework for parameterized subgrid-scale surface fluxes (PASS) has
been modified and applied as PASS1 to use satellite data, models, and limited
surface observations to infer root-zone available moisture (RAM) content with
high spatial resolution over large terrestrial areas. Data collected during
the 1997 Cooperative Atmosphere-Surface Exchange Study field campaign at the
Atmospheric Boundary Layer Experiments site in the Walnut River watershed
in Kansas were used to evaluate applications of the PASS1 approach to infer
soil moisture content at times of satellite overpasses during cloudless conditions.
Data from Advanced Very High Resolution Radiometers on the NOAA-14 satellite
were collected and then adjusted for atmospheric effects by using LOWTRAN7
and local atmospheric profile data from radiosondes. The input variables for
PASS1 consisted of normalized difference vegetation index and surface radiant
temperature, together with representative observations of downwelling solar
irradiance, air temperature, relative humidity, and wind speed. Surface parameters,
including roughness length, albedo, surface conductance for water vapor, and
the ratio of soil heat flux to net radiation, were estimated with parameterization
suitable for the area using satellite data and land-use information; pixel-specific
near-surface meteorological conditions such as air temperature, vapor pressure,
and wind speed were adjusted according to local surface forcing; and RAM content
was estimated using surface energy balance and aerodynamic methods. Comparisons
with radar cumulative precipitation observations and in situ soil moisture
estimates indicated that the spatial and temporal variations of RAM a the
times of satellite overpasses were simulated reasonably well by PASS1.
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Abstract:
The second part of the parameterization of subgrid-scale surface fluxes model
(PASS2) has been developed to estimate long-term evapotranspiration rates
over extended areas at a high spatial resolution by using satellite remote
sensing data and limited, but continuous, surface meteorological measurements.
Other required inputs include data on initial root-zone available moisture
(RAM) content computed by PASS1 for each pixel at the time of clear-sky satellite
overpasses, normalized difference vegetation index (NDVI) from the overpasses,
and databases on available water capacity and land-use classes. Site-specific
PASS2 parameterization's evaluate surface albedo, roughness length, and ground
heat flux for each pixel, and special functions distributed areally representative
observations of wind speed, temperature, and water vapor pressure to individual
pixels. The surface temperature for each pixel and each time increment is
computed with an approximation involving the surface energy budget, and the
evapotranspiration rates are computed via a bulk aerodynamic formulation.
Results from PASS2 were compared with observations made during the 1997 Cooperative
Atmosphere-Surface Exchange Study field campaign in Kansas. The modeled diurnal
variation of RAM content, latent heat flux, and daily evapotranspiration rate
were realistic in comparison to measurements at eight surface sites. With
the limited resolution of the NDVI data, however, model results deviated from
the observations at locations where the measurement sites were in fields with
surface vegetative conditions notably different than surrounding fields. Comparisons
with aircraft-based flux measurements suggested that the evapotranspiration
rates over distances of tens of kilometers were modeled without significant
bias.
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Abstract:
Historically written records of weather conditions that affect agriculture
and living conditions in China can serve as a proxy for instrumental observations
of the relative wetness and dryness, or precipitation amounts, for periods
of time dating back to at least AD 1470. The dryness/wetness index (DW) data
at 100 selected sites and at a subset of 25 sites with entirely continuous
data indicate that during the growing season the number of sites with dryness
increased rapidly in the 20th century, in contrast to a gradual increase and
leveling off of wetness since the 18th century. Dry conditions existed mostly
in northeastern China in the 16th and 17th centuries. In the 20th century,
dryness prevailed in most areas in China, and the chance of occurrence at
each site increased. Wet conditions have expanded from east coastal areas
to inland since the 19th century. As a result of increased dryness and wetness,
the number of sites experiencing normal precipitation conditions has dropped
dramatically. The number of sites with extreme dryness/wetness has also increased
during the 20th century, and the spatial distribution of the sites with a
large chance of extreme dryness/wetness has also changed. The frequent occurrences
in dryness/wetness as well as in extremes in the 20th century seem indicative
of an abnormality in climate on a large scale. Spectral analysis of the DW
data has revealed that cycles in dryness/wetness and their extremes have existed
with periods on relatively short time scales as well as on the long time scales.
The possible existence of a century-scale cycle suggests that caution should
be used in relating variations in rainfall conditions to global warming. Keyword:
historical data, dryness/wetness, extreme events, climate change, China.
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PI, the U.S. Department of Energy, Climate Change Prediction Program 2004-2007, $196,435, The Role of Soil and Vegetation in the Future Climate.
The objective of the project is to develop a dynamic rooting (DR) module that links ground hydrology to ecosystems and carbon cycle in climate model with variant rooting distribution and function in response to climate, and to examine the influence of realistic representation of plant roots on simulated changes in future climate and atmospheric CO 2 . First, a DR module is developed to be plant functional types (PFTs) specific for coupling with one of the comprehensive land surface models; second, the new land surface model with DR is implemented for offline global-scale simulations and optimization of module parameters, and finally, the role of dynamic rooting system in modeling future climate under IPCC scenarios is investigated by performing atmosphere-ocean-land modeling. In addition, the influence of changes in global water cycle and carbon balance on major biomes will be evaluated for distinct climate zones. The research results will help to reduce the uncertainties in the predicted hydrological cycle and carbon budget for the future global change, and will bridge the gap between ecosystem researches with climate modeling.
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PI for "Long-term surface hydrological study at Walnut River Watershed," (Project/Grant G5A 63670) funded by the Department of Energy through Argonne National Laboratory, duration is 05/15/2001 -05/15/2004.
A three-year
pilot study on the terrestrial water cycle began in March for DOE as a collaborative
effort involving several national laboratories. The study focuses on development
and demonstration of techniques to observe and model the components of the
hydrological cycle such as evapotranspiration, precipitation, runoff, storage
as ground water, and changes in soil moisture content. The chosen area of
study is the Walnut River Watershed (WRW), a closed catchment already partially
instrumented by Argonne National Laboratory and DOE's Atmospheric Radiation
Measurement Program. The WRW has an area of approximately 5000 km2 and is
located just east of Wichita, Kansas. Activities at Northern Illinois University's
Department of Geography, under the direction of Dr. Song, will focus on application
of the PASS model to the WRW and, in greatest detail, to the Whitewater subbasin.
Estimates of evaporation and root-zone soil moisture will be made for multiple
seasons and at higher spatial resolution than previously accomplished by PASS.
Benchmarking the results by comparison to field measurements will be routinely
carried out. A multiyear evaluation of all o the hydrological components will
be made. The work at Northern Illinois University will provide scientific
support to other water cycle participants on use of PASS as a land surface
model that can be coupled with mesoscale meteorological models and to couple
PASS with belowground hydrological models. Also data sets produced by PASS
on soil moisture and evaporation amounts will be made available to water cycle
participants.
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