What We Do

CASES-97 (Cooperative Atmosphere Surface Exchange Study)

Project Tabs - CASES97

The Cooperative Atmosphere-Surface Exchange Study 1997 field program (CASES-97) was conducted from late April-mid June 1997, look at the role of atmosphere-surface exchange in the diurnal cycle of the temperature and moisture field in the Walnut River Watershed in SE Kansas, and to improve the representation of the important processes in land-surface models. Flux and mean data from two aircraft (NOAA Twin Otter and University of Wyoming King Air) and 9 surface sites were supplemented with radiosondes, radar wind profilers from Argonne National Laboratory, and gage-corrected precipitation estimates from two radars (S-Pol and the Wichita WSR-88D).

Six-hour daytime average and standard deviation of latent heat fluxes for the period 16 April to 22 May 1997. Models are indicated by name; CASES are surface station observations. Surface stations 1, 2, and 8 are located over grassland/pasture sites, 3 and 4 over sparsely vegetated surface, and 5, 6, and 7 over winter wheat sites.
Six-hour daytime average and standard deviation of latent heat fluxes for the period 16 April to 22 May 1997. Models are indicated by name; CASES are surface station observations. Surface stations 1, 2, and 8 are located over grassland/pasture sites, 3 and 4 over sparsely vegetated surface, and 5, 6, and 7 over winter wheat sites.

This is a continuing collaborative research project funded by NASA Land-Surface Hydrology Program. Participants include David Yates and Fei Chen of RAP/NCAR; Margaret LeMone of MMM/NCAR; Steve Oncley of ATD/NCAR; Richard Grossman of the University of Colorado, and H. Nagai at the Japan Atomic Energy Research Institute. The project's goal is to understand the impacts of surface heterogeneity in soil moisture and surface characteristics on the transport of temperature and moisture in the atmospheric boundary layer.

This research project focuses on the parameterization of subgrid-scale variability for mesoscale and large-scale atmospheric models. One-month observations obtained from CASES-97 were used to create a gridded multi-scale (1, 5, and 10 km) data set over an area of 71x74 km2. Three land-surface models were used to simulate the surface heat flux at these scales. These land-surface models include the relatively simple Oregon State University Land Surface Model (OSULSM), the National Center for Atmospheric Research Land Surface Model (NCARLSM), and the more complex SOLVEG with nine canopy layers and seven soil layers. Preliminary verification demonstrates that these land-surface models reasonably captured the spatial heterogeneity caused by rainfall and surface characteristics at small scales.

Station Overview 

Table: CASES-97 flux-station descriptions. Unless otherwise indicated, all stations measure eddy-correlation latent and sensible heat fluxes, net radiation, heat flux into the soil, temperature, humidity, and wind.

No.

Description

Lat 
(deg N)

Long 
(deg W)

Altitude 
(m MSL)

Station Type

Duration

Comments/additional measurements

1

Grassland, minimal grazing near site

37.5907

96.6517

470

NCAR PAM* III

21 Apr–21 May

Momentum flux, downwelling shortwave radiation, radiometric surface temperature, pressure, precipitation, soil temp and moisture at -5cm.

2

Grassland, minimal grazing near site

37.5518

96.5552

485

NCAR PAM III

21 Apr–21 May

"

3

Bare ground; corn shoots to S and soybean shoots to N by 21 May; adjacent to small patch of winter wheat to E and SE

37.4900

97.0317

357

NCAR PAM III

21 Apr–21 May

"

4

Grass to N; tilled unplanted field to S

37.5932

96.9520

370

NCAR PAM III

21 Apr–21 May

"

5

Winter wheat

37.5035

97.1397

400

NCAR PAM III

21 Apr–21 May

"

6

Winter wheat in floodplain

37.2717

97.0093

345

NCAR PAM III

21 Apr–21 May

"

7

Winter wheat

37.4442

96.9995

365

NCAR ASTER**

21 Apr–21 May

As for 1-6, plus CO 2 and O 3 fluxes, short- and longwave upwelling and downwelling radiation, weekly soil moisture profiles to -70 cm

8

Grassland, no grazing

37.4007

96.9467

410

NCAR ASTER

21 Apr–21 May

As for 1-6, plus “veggie-meter”; weekly soil-moisture profiles to -90 cm

9

Grassland, no grazing

37.738

97.184

418E

CU (Qualls)

21 Apr–21 May

Soil temp, soil moisture at -4 cm

10

Grassland, minimal grazing near site

37.4647

96.8102

424E

NOAA ATDD

7-21 May

Pressure, precipitation, soil moisture and temperature profiles to 60 cm; CO 2 and O 3 flux

11

Grassland, some grazing

37.521

96.855

408

ABLE (ANL)

26 Apr-present

Precipitation, pressure; only flux sampled during experiment was sensible heat

12

Alfalfa to S

37.842

97.020

409

ARM

Dec 1995 - Present

Minimal data during CASES-97

*Portable Automated Mesonet III (Horst and Oncley 1995, Militzer et al. 1995), which provided 10-20Hz data as well as averaged fluxes.

** Atmosphere-surface turbulent exchange research facility (Businger et al. 1990)

Photo Gallery

 

  • Station 1
    • site1.970419.45se.jpg
    • site1.970419.e.jpg
    • site1.970419.n.jpg
    • site1.970419.s.jpg
    • site1.970419.w.jpg
    • site1.970501.e.jpg
    • site1.970501.n.jpg
    • site1.970501.s.jpg
    • site1.970501.w.jpg
  • Station 2
  • Station 3
  • Station 4
  • Station 5
  • Station 6
  • Station 7
  • Station 8
  • Station 9
  • Station 10

 

 

Data Archive

http://www.ral.ucar.edu/research/land/observations/cases97/archive/

LeMone, M.A., F. Chen, J.G. Alfieri, M. Tewari, B. Geerts, Q. Miao, R.L. Grossman, and R.L. Coulter, 2006: Influence of land cover, soil moisture, and terrain on the horizontal distribution of sensible and latent heat fluxes and boundary layer structure in southeast Kansas during IHOP_2002 and CASES-97. J. Hydrometeorology. In press.

Alfieri, J.G., D. Niyogi, M.A. LeMone, F. Chen, and S. Fall, 2006: A simple reclassification method for correcting uncertainty in land use/land cover datasets used with land surface models., Submitted to IMPA Special Issue for Atmospheric Environment.

Miller, N.L., A.W. King, M.A. Miller, E.P. Springer, M.L. Wesely, K.E. Bashford, M.E. Conrad, K. Costigan, P.N. Foster, H.K. Gibbs, J. Jin, G. Klazura, B.M. Lesht, M.V. Machavaram, F. Pan, J. Song, D. Troyan, and R.A. Washington-Allen, 2005: The DOE Water Cycle Pilot Study. Bull. Amer. Meteor. Soc., 86, 359-374.

Grossman, R.L., D. Yates, M. LeMone, M.L. Wesely, J. Song, 2004: Observed effects of horizontal surface temperature variations on the atmosphere over a midwest watershed during CASES-97. J. Geophys. Res., 110, DO6117, doi:10.1029/2004JD004542.

Chen, F., D. N. Yates, H. Nagai, M. A. LeMone, K. Ikeda, and R. L. Grossman, 2003. Land-Surface Heterogeneity in the Cooperative Atmosphere Surface Exchange Study (CASES-97). Part-I: Comparing Modeled Surface Flux Maps With Surface-Tower and Aircraft Measurements. . J. Hydrometeorol., 4, 196-218.

Yates, D.N., F. Chen, and H. Nagai, 2003. Land-Surface Heterogeneity in the Cooperative Atmosphere Surface Exchange Study (CASES-97). Part-II: Analysis of spatial heterogeneity and their scaling. J. Hydrometeorol.4, 219-234.

LeMone, M., R. Grossman, F. Chen, K. Ikeda, and D.Yates, 2003. Choosing the averaging interval for comparison of observed and modeled fluxes along aircraft transects over a heterogeneous surface. . J. Hydrometeorol., 4, 179-195.

LeMone, M.A., K. Ikeda, R.L. Grossman, and Mathias Rotach, 2003: Horizontal Variability of 2-m temperature at night. CASES-99 Special Issue . J. Atmos. Sci. 60, 2431-2449.

Song, J. and M.L. Wesely, 2003: On comparison of modeled surface flux variations to aircraft observations . Agric. Forest Meteor. ,117, 159-171.

LeMone, M., R. Grossman, R.T. McMillen, K.N. Liou, S. Ou, S. McKeen, W. Angevine, K. Ikeda, and F. Chen, 2002. CASES-97: Late morning warming and moistening of the convective mixed layer over the Walnut River watershed. Boundary Layer Meteorol , 104, 1-52.

Yates, D.N., F. Chen, R. Qualls, M. LeMone, and S. Oncley, 2001: A Cooperative Atmosphere-Surface Exchange Study (CASES) Dataset for Analyzing and Parameterizing the Effects of Land Surface Heterogeneity on Area-Averaged Surface Heat Fluxe. J. Appl. Meteorol.40, 921-937.

Wesely, M. L., J. Song, R. T. McMillen, and T. P. Meyers, 2001: Effects of soil moisture variations on deposition velocities above vegetation . Water, Air, and Soil Pollution Focus 1, 1-4.

Yates, D.N., F. Chen, M.A. LeMone, R. Qualls, S.P. Oncley, R.L. Grossman, and E.L. Brandes, 2001 A Cooperative Atmosphere-Surface Exchange Study (CASES) dataset for analyzing and parameterizing the effects of land-surface heterogeneity on area-averaged surface heat fluxes . J. Appl. Meteorol. , 40, 921-937.

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 . J. Hydrometeor. , 1, 462-473.

Coulter, R. L., G. Klazura, B. M. Lesht, J. D. Shannon, D. L. Sisterson, and M. L. Wesely, 1999: The Argonne Boundary Layer Experiments facility: Using minisodars to complement a wind profiler network. Meteorol. and Atmos. Physics 71, 53-59.

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