APPENDIX B

SUMMARY OF RESULTS FROM GCIP/LSA-E DETAILED DESIGN WORKSHOP

The GCIP/LSA-E Detailed Design Workshop was held in Huntsville, Alabama on 20 - 22 October, 1996 at the Holiday Inn - Research Park. The primary purpose of this workshop was to provide inputs to the design of the overall experiment for the LSA-E during the water years 1998-1999. The Workshop made use of the document entitled "GCIP Studies in the LSA-E - A Discussion Paper" compiled by Dale Quattrochi as a starting point in developing recommended research activities. This Appendix contains a preliminary summary of the results from the Workshop. A more complete summary is in preparation.

The characteristics of the major river basins in the LSA-E are:

The features of the Ohio and Tennessee River basins important to the GCIP continental- scale studies include the following: The features and characteristics losted above led to the emphasis on research studies and modeling for this region to focus on the annual hydrometeorological cycle dynamics and water resources management.

B.1 LSA-E Infrastructure and Related Research

A significant part of the Workshop was a series of presentations on the existing facilities and current research activities in the region which are potentially useful for collecting data needed by GCIP and/or for cooperative research studies with GCIP. D. Quattrochi provided an overview of the potential GCIP studies in the LSA-E region to begin in 1998. His presentation summarized the discussion paper which he had compiled and which was sent to all the participants prior to the workshop. His discussion included an examination of potential important science issues that need to be addressed within the LSA-E. Possible links with other projects were also discussed.

Global Hydrology and Climate Center

R. Greenwood described the Global Hydrology and Climate Center (GHCC) which was established by NASA's Office of Mission to Planet Earth and is a partnership comprised of organizational elements from NASA Marshall Space Flight Center (MSFC), the Space Science and Technology Alliance (SSTA) of the State of Alabama and the Universities Space Research Association (USRA). NASA's main focus is on research, education, flight programs, information systems, and advanced studies. SSTA's main focus is education, research, regional studies, and information systems. USRA's main focus is in research, education programs, and visiting scientist programs.

GHCC's charter is to build a nationally-recognized program in global hydrology. The primary focus of the research center is to understand the Earth's global water cycle, the distribution and variability of atmospheric water, and the impact of human activity as it relates to global climate change. The main research areas of GHCC are climate studies, hydrology, passive microwave measurements, atmospheric electricity, and aerosol/doppler measurements.

Alabama A&M University's Center for Hydrology, Soil Climatology, and Remote Sensing (HSCaRS)

T. Tsegaye described the activities of HSCaRS which was established by NASA's Equal Opportunity Office to conduct research activities that are pertinent to NASA's mission goals and strategic enterprises. The mission of HSCaRS is to develop a comprehensive research program involving hydrologic processes with emphasis on remote sensing measurements and modeling, and to develop an educational curriculum that will increase the productivity of under-represented minorities with advanced degrees in NASA-related fields. This Center is expected to be a source of trained scientists to address research topics of interest to GCIP.

The initial focus of the Center's research is on soil moisture remote sensing and hydrologic modeling, with particular emphasis on the use of remotely-sensed soil moisture data in hydrologic models. An initial experiment in soil moisture was conducted in July 1996 in Huntsville, AL, with passive and active microwave remote sensing instruments deployed from boom-trucks.

USDA/ARS Hydrologic Activities in the Ohio and Tennessee River Basins and Neighboring Areas

C. Alonso informed the participants that the USDA/ARS has three experimental watersheds in the vicinity of the LSA-E: (1) Goodwin Creek watershed,MS; (2) North Appalachian Experimental watershed near Coshocton, OH; and, (3) East Mahantango Creek, PA. Only the North Appalachian Experimental watershed is contained within the boundaries of the LSA-E. Because of the small size of these watersheds with respect to the LSA-E, it is thought that these sites would represent points in a larger-scale data set and could serve as calibration sites. He summarized the physiography of the sites, their climatology and the variables that are measured on a regular basis. Of notable importance, NOAA's Air Resources Laboratory is operating a SURFRAD station in the Goodwin Creek watershed to collect comprehensive surface radiation budget data.

Tennessee Valley Authority (TVA) Research and Facilities

R. Ritschard described the Tennessee River, which drains about 106,000 sq. km, as a heavily managed river system. It is managed by the Tennessee Valley Authority, which contains portions of seven states. TVA's function is two-fold: electric power and stewardship. Stewardship takes place through regional economic development, natural resource conservation, and environmental research.

TVA has over 60 years of operational experience, compiled data bases of long records, has developed and applied models and analytical methods, retains scientists and engineers with expertise in hydrology, water and air pollution, and land cover characterization. TVA runs two different watershed hydrology models, a modified Sacramento model and a statistical watershed model. It operates three different water quality models, two fish habitat and response models, a systems water temperature and water quality model, a reservoir systems model, and a decision support modeling system. TVA collects data from 292 rain gages, 75 streamflow gages shared among various agencies, hourly reservoir data on headwater and tailwater elevation, turbine and total discharge, and meteorological data from three stations. TVA also has a repository of aerial photography, and GIS data from specific projects.

Walker Branch Experimental Watershed at the Oak Ridge National Laboratory

P. Hanson described the research activities in the Walker Branch Experimental Watershed which is a small (97 ha.) tributary to the Clinch river just north of Oak Ridge National Laboratory, TN. The site is covered with deciduous hardwood forest and contains two perennial streams. The watershed is currently the site of a throughfall displacement experiment, carbon flux, watershed evapotranspiration and saturated throughflow research. A 44 m walk-up tower with meteorological instruments is located at the site in conjunction with the carbon flux research. A National Acid Deposition program site is located on the periphery of the watershed.

NWS Ohio River Forecast Center, Wilmington, OH

T. Adams described the operational river forecast activities within the Office of Hydrology in the National Weather Services of NOAA. The NWS River Forecast Center (RFC) system is an operational system that offers interactive capability to monitor river forecast simulations. Embodied within the RFC system is a calibration system and an extended streamflow prediction system. The RFC system offers the capability for flash flood guidance within the Ohio River and Lower Mississippi River RFC areas. Current operation of the Ohio River Forecast Center (ORFC) is 17 hours per day, 7 days a week. The ORFC offers one daily forecast with updates provided as needed. The ORFC produces daily quantitative precipitation forecasts (QPF), lumped modeling, flash flood guidance calculations and routine verification of river stage forecasts. There is no current use of WSR-88D radar in QPF's. The ORFC breaks the Ohio River basin into 29 forecast groups for modeling analysis. Adams noted there are significant challenges in hydrological forecasting. These are related to data availability, poor resolution of data, incomplete or missing data, and quality control. Additionally, the complexity of the overall Ohio River basin hydrology causes problems in river forecasting. The problems here relate to snow melt prediction, river ice (location and extent) and freezing of gages in winter. He provided some idea on where the RFC is going in the future by moving more towards distributed hydrologic modeling, better snow estimations and updating in the Eastern U.S., integrating GIS procedures into forecast modeling, developing an advanced hydrologic prediction system and incorporating problemlistic forecasting, deriving more automated data input - especially from remote sensing.

Incorporating Probablistic QPF into Streamflow Predictions

J.Schaake presented some projections on how streamflow predictions in the future will be handled. There are several fundamental questions driving how probabilistic QPF's will be incorporated into streamflow predictions in the future: 1) What do users want ? 2) What do users need? And, 3) What can we do? Basically, users want us to tell them what can happen and want to know how sure we are that it will happen. He showed a number of illustrations that diagram the hydrologic forecasting scenario. Schaake also illustrated the overall relationship of Ensemble Streamflow Prediction (ESP) in response to observed streamflow through time. He noted that ESP methods are needed to predict future river stages, flows, etc, and that these predictions depend on upstream precipitation patterns over time and space. Schaake identified four approaches that may be used in creating ensembles: 1) Climatology only; 2) Modify climatology using forecasts; 3) Generate short-term forecasts using QPF's and space-time correlation; and 4) Use of an atmospheric ensemble. He stated there are currently two areas that are being used as NWS forecast demonstration projects: The Des Moines and the Monongahela River basins. The Des Moines river basin study will begin in March, 1997 during the spring flood season. Forty-one subbasins within the Des Moines river basin will be used in the study for user definition of flood forecast products. The Monongahela River basin study will begin in the fall of 1997. Here, three headwater basins will be used for modeling in conjunction with 24 hour probabilistic QPF models. The driving factor in this demonstration study is to define alternative strategies to get streamflow and river stage probabilities correctly modeled. Schaake closed with several science questions that must be addressed in QPF probablistic modeling: 1) What are the relationships between modeled and real values?; 2) How can these modeled values be quantified?; 3) How do the values change as the models change?; and 4) What is the role of the forecaster in QPF probabilistic modeling?

B.2 Work Sessions

Work Sessions were held in two phases. The first phase addressed three specialized topics while developing an approach to the major research questions on the annual hydrometeorology and water resources that are significant to the success of GCIP. The three topics were: The second phase then further developed the specific research and data issues defined during these initial Work Sessions.

GCIP research addresses activities on two scales in each Large Scale Area (LSA). Intermediate-scale area (ISA) activities at spatial scales on the order of 1,000 to 10,000 sq km are phased in with those for each LSAs. Small-scale area (SSA) activities at a spatial scale on the order of 100 sq km typically involve efforts requiring intensive observing periods over a concentrated region to study focused issues. The Work Sessions were asked to identify candidate ISA and SSA activities in the LSA-E.

B.3 Coupled Hydrologic/Atmospheric Modeling Work Session

The development and validation of coupled hydrological-atmospheric models is a major scientific objective for GCIP that includes improving the representation of land surface components in models. This Work Session was asked to consider how GCIP can make use of the unique features, infrastructure and data available in the LSA-E to develop and evaluate regional coupled hydrologic/atmospheric models for weather and climate prediction. In particular, it addressed questions such as what coupled modeling issues can be addressed in the LSA-E?; what processes pertaining to characteristics inherent to the LSA-E need to be emphasized?; how can we evaluate the capability of coupled models to simulate the causal mechanisms for interseasonal and interannual variability over the LSA-E?; and what is needed to estimate model parameter values over the annual hydrologic cycle?

The Work Session was also asked to identify the types of data needed for hydrological and atmospheric modeling research; to identify where such data are available in the LSA-E; and to recommend enhancements to assure sufficient data are available for the Water Years 1998 and 1999.

The coupled hydrologic-atmospheric modeling Work Session recommended research tasks in four areas and summarized in the remainder of this section.

B.3.1 Model Grids and Coordinate Systems

The current status of the three regional models being used by GCIP to provide model output data for budget studies and other applications was reviewed with emphasis on the capability to produce the model output needed during the Water Years 1998 and 1999.

The three regional models producing output for GCIP are archived on a 40 km resolution grid using a Lambert Conformal Map projection true at 100W longitude. However, the "native" grid system resolution varies among the three models. These variations provide an opportunity to investigate the extent to which each of the three regional model grid and coordinate systems are adequate to model the effect of orography on precipitation and the effect of heterogeneous vegetation in the LSA-E.

However, these evaluations should include comparisons with higher resolution grids. The Eta model produced model output at 10 km resolution over a portion of the LSA-E during the period of the 1996 Olympics in Atlanta, GA. A model output data set such as this is well suited for comparative evaluation on the effects of grid resolution in capturing orographic effects on precipitation and the effect of heterogeneous vegetation.

B.3.2 Model Initiation

The Work Session considered there is little data available in LSA-E for coupled hydrologic/atmospheric modeling in both the operational and the research mode. It was recommended that sensitivity studies be conducted on the effects of improved initiation of coupled mesoscale models in very complex regions (such as the LSA-E) with special attention to orography, vegetation, groundwater, and heavily managed runoff.

It was suggested that a coupling between the Land Data Assimilation System (LDAS) and hydrological models and applied in the Ohio and Tennessee river basins could be a test bed for some of these sensitivity studies.

B.3.3 Modeling Clouds

The Work Session recognized that all aspects of cloud parameterization in atmospheric models could be improved. However, it was recommended that some emphasis should be placed on the problem of representing low-level cumulus clouds. The feedback on the surface energy balance needs to be included in coupled mesoscale models and the parameterization of such clouds evaluated using detailed, satellite based estimates of cloud cover.

B.3.4 Compatibility of Regional and Global Models

It was considered that the relative value of output from regional and global models is largely an open question in the case of LSA-E, and that this may have seasonal characteristics. The Work Session recommended that some priority be given to the evaluation of global model output using regional data sets from the LSA-E. In this regard, it was recommended that GCIP give consideration to the following questions. B.4 Diagnostic Studies/Energy and Water Budgets Work Session Determining the time and space variations of the energy and water budgets from daily to seasonal and interannual periods for the continental scale is one of the scientific objectives for GCIP. This Work Session was asked to consider the types of energy and water budget studies that could best be done in the LSA-E that could contribute to the successful achievement of this scientific objective for GCIP. This Work Session was also asked to identify the data requirements needed to conduct energy and water budget studies; to consider how the existing facilities could contribute to these budget studies; and to recommend enhancements to the existing facilities which the GCIP Project should make during the two-year data collection period of Water Years 1998 and 1999.

The Work Session was focused on energy and water budgets and their variations on seasonal to interannual time scales. The primary questions it addressed were:

The Working Group was asked to make specific recommendations with respect to: The Group in the Work Session noted that given the overall complexity and heterogeneity of the LSA-E it would be exceedingly difficult to design an observational program that could sample data representative of each micro-climate and ecosystem niche. Thus the group suggested that it would be prudent to suggest the minimum number of SSAs that would sample two major ecosystem types, forests versus cultivated land areas, and regions with distinctive climates, northern versus a southern areas. A survey of existing instrumented sites resulted in recommending that the following sites be considered as candidates for SSA sites: The Working Group recommended augmenting or changing locations for the current MOLTS array produced by the coupled mesoscale models to include the candidate SSA sites listed above.

As in all GCIP study areas, precipitation was identified as the most critical variable. It was recommended that the current GCIP mosaic precipitation data set be checked to insure that it was obtaining all of the precipitation networks within the LSA-E. Given the complex terrain and potentially large amounts of data it was suggested that the WSR-88D estimated rainfall would be most useful in conjunction with SSA and ISA study areas.

B.5 Hydrometeorological Prediction and Water Resources Management

The water resources working group focused on how GCIP LSA-E activities could contribute to GCIP's evolving goals with respect to water resources. The group started by identifying some of the most important characteristics of LSA-E with respect to water resources:

B.5.1 Relationship to Ongoing NWS Activities

Present operational hydrologic forecast models in use at the two NWS RFCs in LSA-E and by water management agencies do not include new representations of vegetation that have been developed by the land surface community, do not model the surface energy budget, and generally make limited use of available soils, land use and remote sensing information. On the other hand the land surface models are beginning to include hydrologic components that account for infiltration, surface runoff, and subsurface runoff and water storage. As GCIP begins to focus on the LSA-E, subsurface storage and runoff processes will need to be represented well in the land surface models. This will be required for these models to represent the surface moisture conditions that actually exist in the LSA-E and that are important for surface forcing of the atmosphere in climate models as well as weather prediction models. On the other hand, operational hydrologic prediction models would be significantly improved if they included better and more physically based representations being developed by GCIP for application in atmospheric models and for use in LDAS to provide initial soil moisture and temperature information for NWP models.

NWS is developing an ensemble precipitation forecasting capability. This will use ensemble forecasts from regional and global numerical prediction models, but it will include a range of statistical approaches to processing model output information, for simulating fine scale space-time characteristics of precipitation not represented in model output, and for accounting for short-term forecast uncertainty that may not be included in NWP ensemble products. This also includes development of a precipitation snalysis system to be used at RFCs that will include various statistical tools for combining all of the information from different sources and for producing the final precipitation ensembles for the hydrologic models.

B.5.2 Relevance of GCIP Plans to Water Resources Operations in LSA-E

TVA has an interest in streamflow forecasts with two lead times: a) for operational purposes (up to about a week); and b) for planning purposes (months to seasonal). At present, TVA uses probabilistic (10, 50, 90 percentile) forecasts derived from NCEP products; these are used as forcings in the Lettenmaier/Grygier/Stedinger model streamflows (Sacramento model for five index catchments disaggregated stochastically to 42 inflow nodes). For planning purposes, an analogue approach is used, wherein historical observed streamflows for selected years are routed through a reservoir system model. In addition to inflows to the reservoir system, TVA has an interest in forecasts of surface air temperature, which affect both water temperature, which is a key operating constraint, and power demand.

The PRSYM model was implemented by a research group, and is not currently used operationally by TVA. The ESP approach is not used operationally at present in LSA-E, either by the NWS River Forecast Centers, or by TVA. There is a potential TVA interest in ESP-type forecasts over a range of time scales from several days (for power operations purposes) through seasonal (for power planning).

The NWS scheme(s) for producing QPF are evolving. For short lead times (out to about two days), forecasts will be produced from Eta model output. Because the source of forecast uncertainty is not entirely clear at short lead times (probably a combination of uncertainty in model initialization, parameter error, and residual error due to subgrid effects) it will be necessary to develop schemes to represent, possibly via rescaling, forecast error probability density functions. At longer time scales (up to two weeks), ensemble forecasts will be produced using the NCEP's global model. At these lead times, ensemble predictions are expected to represent more realistically the range of likely forecast errors. Finally, at seasonal time scales, ensemble forecasts will be developed from NCEP's coupled ocean-atmosphere model.

B.5.3 Recommendations

Improvements in short and long-range weather forecasting represent the strongest tie between the GCIP research community and water resources operations, both generally and for LSA-E in particular. As a means to direct the LSA-E water resources activity in this direction, the feasibility of developing an experimental water resources forecast capability for part or all of LSA-E was recommended, as follows:

B.6 Research Issues Work Session

This Work Session used the results from the first set of Work Sessions to develop an overall listing of the research topics which GCIP should concentrate on during the period of 1997 and 1998 for focused studies on cold season/region hydrometeorology in the LSA-NC. It was agreed that: The following items were recommended: One other aspect that needs to be undertaken is to evaluate and improve GOES and polar orbiting data for surface radiation budgets, radiative flux estimates, and to develop data sets for flux profiling of surface fluxes. It was suggested there be development of the LDAS concept, both for operational and research uses, and, to develop a strategy to validate with streamflow gauging with emphasis on focus study areas.

It was recommended that GCIP/DACOM include the following sites in their inventory of data available in the LSA-E.

Additionally, land-grant universities within the LSA-E (i.e., agricultural schools) should be contacted to find out if they monitor any flux tower sites and instrumented watersheds within the LSA-E. Potential schools are: University of Tennessee, Knoxville; University of Kentucky; University of Georgia; Auburn University; Mississippi State University; Ohio State University; West Virginia University; Virginia Tech as well as possibly others.

B.7 Data Issues Work Session

This Work Session used the results from the first set of Work Sessions to develop a consolidated list of data requirements for the LSA-E. The Work Session started with the strawman"list of data requirements which had been developed prior to the workshop. Several possible additions of data from states within and just outside the LSA-E were discussed. This included the Georgia Forestry Commission (28 meteorological stations), the Alabama Weather Observing Network (several automatic meteorological stations) and Alabama Redstone (18 meteorological stations), the North Carolina State Network (14 meteorological stations). Possible additions to upper-air data include profiler data from Redstone Arsenal, University of Alabama-Huntsville (UAH) and Oak Ridge, Tennessee. The consolidated list which resulted from a discussion in a Plenary Session at the Workshop was given in Section 12 of this report.

The group recommended the following actions for GCIP in preparation for research activities in the LSA-E:

The group raised a number of questions pertaining to the availability and use of satellite remote sensing data in the LSA-E. The Session was informed that the MSFC/DAAC as the current satellite remote sensing data source module Work is developing a detailed survey of data availability through remote sensing satellites affecting the LSA-E.