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RAP Achievements

F. Water Resources

[Background] [Surface hydrology]
[Water resource evaluation]
[Hydrologic aspects of land-atmosphere]
[NAME project] [CUAHSI]
[AWWA Research Foundation]
[United Arab Emirates]

 


1. Background

RAP's water resource-related activities were considerable in FY04. Research expanded into flash flood nowcasting as part of an NCAR Opportunity Fund study and new work in climate change research methods for water resource assessment was partially supported by NCAR’s Climate and Weather Impact Assessment Science Initiative (CWIASI). RAP’s land surface modeling work was advanced through the addition of a new 2-D overland flow routing parameterizations to the NOAH Land Surface model, the land surface model used by the Weather Research Forecasting (WRF) mesoscale model and the Mesoscale Model Version 5 (MM5). RAP also played a major role in the North American Monsoon Experiment’s (NAME) Intensive Observing Period (IOP) in Summer 2004 by the deployment and analysis of a comprehensive rain gage network, and establishing an operational mesoscale forecasting model applied during the IOP.



2. Surface hydrology for urban flash flood autonowcasting

Denver’s Urban Drainage and Flood Control District (UDFCD) manages the ALERT (Automated Local Evaluation in Real Time) urban flood warning system, whose aim is to reduce injuries, deaths, and property damage caused by floods. Floods in urban and semi-urban environments are the leading cause of weather-related accidental death in the U.S. The goal of this 2004 Opportunity Fund project was to demonstrate the usefulness of NCAR’s Thunderstorm Identification Tracking and Analysis (TITAN) data in support of the UDFCD flood threat monitoring and dissemination mission.

Figure F-1 is a flow diagram showing how radar data are combined to produce watershed-specific estimates and 30- min forecasts of rainfall accumulation over specific, GIS-specified UDFCD watersheds. These data are transformed into XML format, placed on an ftp server for broadcast, and then picked up by web-based and Microsoft Excel© tools operated by the UDFCD for visualization of storm movement and basin discharge estimates and forecasts.

 

Figure F-1. Data flow diagram of basin precipitation estimates and forecast products.

Two outputsare produced by the UDFCD based on the XML data distributed in real time on an NCAR ftp server as depicted in Figure F-1. These include estimates and forecasts of basin runoff of Boulder Creek (Figure F-2a) and a radar image display that shows TITAN storm tracks and precipitation threshold of the Lena Gulch Watershed for 9 June 2004 (Figure F-2b). [Top]

a)                                                                                         b)

Figure F-2 a) UDFCD basin runoff estimates (blue-line) and forecasts (red-line) for the Boulder Creek watershed, based on the XML distributed file shown in Figure F1; b) UDFCD Scalable Vector Graphics (SVG) display of background radar reflectivity, current TITAN storm locations given as ellipses (ellipse color depicts reflectivity intensity, with scale not shown).

In addition to this work, Hatim Sharif, David Yates, Rita Robers, and Cindy Mueller applied RAP’s Auto-Nowcast (ANC) system to flood forecasting. ANC combines a host of remotely sensed data, including gridded radar fields, surface mesonet data, sounding data, satellite data, etc. to produce 0-60 min quantitative precipitation nowcasts through deterministic and fuzzy logic algorithms. The potential benefits of ANC precipitation nowcasts were demonstrated by forcing them through a physically-based, distributed hydrologic model to predict flash floods in a small, highly urbanized catchment in Denver, CO. Two rainfall events on 5 and 8 July 2001 in the Harvard Gulch watershed corresponding to times during which the ANC system operated (Figure F-3) were analyzed. In addition to analyzing the nowcasts for these events, the 8 July case was used to evaluate the hydrologic model’s ability to accurately reproduce the watershed’s response to the precipitation forcing based on either rain-gage or high-resolution radar estimates.

 

Figure F-3. The Harvard Gulch watershed, with storm-total radar estimated rainfall, and location of USGS rain gauges are depicted. The street network of the urban area are shown in the background.

 

 

 

 

 



3. Water resource evaluation of rainfall enhancement - Oman


D. Yates and Roelof Bruitjes finalized a study for the Sultanate of Oman that addressed the feasibility of rainfall enhancement for man-made increases in groundwater recharge. The availability of water for domestic, agricultural and industrial use in many parts of Oman has been a critical problem for many years. The country is located in the semi-arid and hyper-arid regions of the Arabian Peninsula, with the Al Hajar al Ghabri (Oman Mountains) range extending near and along the Batinah coast with annual precipitation ranging from < 50 mm in central Oman to > 300 mm in the mountains, with large spatial and temporal variability. Although a major portion of the population is concentrated along the coast, where desalinized sea-water accounts for the majority of the potable supply, the interior region is experiencing increased water shortages due to increases in demand and recent droughts. Decreasing ground water level is one of the most pressing problems in these interior regions. The authorities in Oman are exploring possibilities to augment water resources via methods such as cloud seeding to enhance rainfall. [Top]

The final report noted the slightly higher annual average rainfall in the northern part of the Oman Mountains, while a second maximum was located further to the southeast, in more mountainous terrain. The seasonal distribution of rainfall helps explain these differences, as the northern precipitation maximum is more strongly influenced by winter- time precipitation. In the winter and early spring, cold frontal troughs originate in the North Atlantic and Mediterranean Sea and move south across the United Arab Emirates toward the Oman mountains. Summer rainfall maxima (bottom panel of Figure F-4), exhibit the suspected strong relationship between rainfall and topography. The rainfall footprint of the southern Al Hajar al Gharbi mountain range is larger than that of the north, since the orographic influence dominates. Given the frequency of convection over the Oman Mountains in the summer, it was concluded that storms over Oman should be amenable to seeding with hygroscopic flares and that acquisition of a modern weather radar is necessary to begin longer-term evaluation.

Figure F-4.



4. Hydrologic aspects of land-atmosphere associated with CASES-97


The article, “Observed Effects of Horizontal Radiative Surface Temperature Variations on the Atmosphere Over a Mid-west Watershed During CASES 97”, co-authored by R. Grossman, D. Yates, Peggy LeMone, M. Wesely and J. Song was accepted for publication in the Journal of Geophysical Research. The study showed the association between ~10-km scale horizontal variations of radiometric surface temperature (Ts) and aircraft-derived fluxes of sensible heat (H) and moisture (LE) using aircraft, surface, and satellite data from a Cooperative Atmospheric-Surface Exchange Studies field program, which took place in the southern part of the Walnut River (Kansas) watershed in April and May 1997. H and Ts reached maxima in the same longitude zone on two flight tracks 40 km apart. Satellite Ts data from March to June reveal similar persistent patterns with minima more persistent than maxima. Two mechanisms are suggested to explain the association of H and Ts maxima:

1) for winds between 6-8 ms-1 , modulation of the surface energy budget by vegetation effects, or

2) for winds equal to or below 4 ms-1 , a thermally-driven circulation centered on Ts maxima. Both mechanisms were possibly enhanced by increased static instability over the Ts maxima.



5. NAME Water Resources Research Project

During Summer 2004, the multinational, multi-institutional, North American Monsoon Experiment (NAME) executed its principal field campaign, or Enhanced Observation Period (EOP). Numerous instrument platforms including weather radars, atmospheric sounding systems, wind profilers, rain gauges, aircraft and ocean vessels were deployed to the 'Tier I' region (See Figure F-5; box bounded by dotted line) of southwestern North America. These instruments monitored surface and atmospheric conditions during the summer rainy season in July and August. David Gochis serves as a member of the NAME Science Working Group, which directs NAME research activities and also serves as a Principal Investigator in the NAME program. Under this role D. Gochis built a Geographical Information System (GIS) database to aid in the planning and implementation of the EOP instrument network. With colleagues at the University of Arizona and in Mexico, D. Gochis has been working on diagnosing and modeling key aspects of the rainfall climatology in western Mexico and its relationship to regional streamflow. This work has culminated in the production two recent manuscripts describing the topographic dependency of diurnal rainfall characteristics in western Mexico, and the intra-seasonal evolution of streamflow in response to monsoon rains.

[Top]

Figure F-5. 2004 NAME EOP Instrument Network.



6.
CUAHSI

The Consortium of Universities for the Advancement of Hydrological Sciences, Inc. (CUAHSI) is a National Science Foundation-sponsored initiative charged with developing a progressive agenda and infrastructure for hydrological research. During FY04 CUAHSI solicited 10-year vision statements from the hydrological community to define strategic goals and opportunities in hydrological research. D. Gochis and other NCAR collaborators prepared a vision statement outlining key needs and emerging opportunities for advancing research in coupled land-atmosphere interactions. Special needs related to improving the understanding of surface-boundary layer-atmosphere transfer processes are outlined and emerging instrumentation platforms are discussed with regards to their expected impact on land-atmosphere interaction research. The vision statement ends with a proposal to develop a community land surface parameterization testbed facility in which new model formulations and emerging data streams can be rapidly tested and implemented into operational weather and climate prediction models.



7. AWWA Research Foundation Climate Change Primer

The collaboration between NCAR’s Research Applications Program and the Environment and Societal Impacts Group with the AWWA (American Water Works Association) Research Foundation advanced in FY04, with a workshop held on 16 March 2004. The workshop brought together water utility planners and climate scientists to discuss the scientific basis of climate change to address how water utilities might plan appropriately for the effect of global warming on water resources. The workshop also facilitated communication between specialists in climactic change and professionals in water utilities to guide future research directions.

This project completed a useful and timely primer to help water managers incorporate climate change information into their planning process. The workshop highlighted the difficulty in incorporating climate change into water management decisions, mainly due to the layers of uncertainty inherent in assessing climate change impacts. For example, uncertainty in projected greenhouse gas emissions, limitations of climate models, and loss of accuracy when climate forecasts are downscaled to watershed resolution and imperfections in hydrological models, are all relevant.

A review of the scientific and water planning literature suggests that most water resource and water utility studies have incorporated climate change information into their planning process using a top-down approach. This approach typically begins by establishing the scientific credibility of climate change, develops future climate scenarios that can be used at the regional level, and then imposes those potential changes on water resource systems for assessing, for example, system reliability. The problem with a top-down approach is that it is not always driven by the unique needs of a utility and also the approach is rooted in the uncertainty of the future climate projections, those projections differing substantially from model-to-model and from region-to-region. Thus, the results are often disregarded for lack of relevancy and reliability.

The primer to be submitted to the AWWA Research Foundation in late 2004 will suggest alternatives to this approach, including a bottom-up strategy which begins by identifying a water utility's most critical vulnerabilities; articulates the causes for those vulnerabilities; suggests how climate change, climate variability, and climate extremes might exacerbate those vulnerabilities; and finally designs an analytic process to better address and solve the vulnerability in the face of the climatic uncertainty (e.g. a no-regret approach). At the heart of either top-down or bottom-up approaches is Integrated Water Resource Management (IWRMM), which is regarded as the most effective approach for assessing and changing the regulatory environment with its competing demands, whose methods will be further articulated in the primer.

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Figure F-6.



8. United Arab Emirates - 4-Dimensional Earth Information System (4D-EiS).

A new project began between the Department of Water Resource Studies (DWRS) in Abu Dhabi, United Arab Emirates (UAE), and NCAR, where RAP (Roelof Bruintjes and Tara Jensen) is implementing a customized hydro-meteorological analysis and display system for the DWRS. The main components of this system include a numerical weather prediction and analysis module based on MM5, running on a 48-node Linux cluster system; a geospatial database containing historical and real-time observations from meteorological and hydrological platforms, and model analysis fields; a tool to perform complex queries to the database; a display system giving the user an integrated view of the geospatial database holdings with flexible controls that include layering GIS information from commercial GIS tools; and providing connectivity of the geospatial database to third-party GIS vendor tools, such as ESRI’s ArcView or ArcInfo.

The last ten months have seen the initial deployment of the system. Figure F-7 shows a beta version of a hydrometeorology display (uaeViz) giving Real Time Four Dimensional Data Assimilation (RTFDDA)/MM5 forecasts of air temperature (colored grid) and contoured relative humidity. In addition, the system is now capable of creating custom reports based on the selection of meteorological stations and meteorological fields from which to derive climatological statistics (Figure F-8).

Figure F-7. UAE-Visualization of RT-FDDA forecast output over the United Arab Emirates, the Arabian Gulf and the Gulf of Oman.

 


Figure F-8. The custom query tool showing the generation of average daily temperature and relative humidity for select station in the UAE.

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RAP Achievements

Director's Message |Table of Contents | Executive Summary |RAP Achievements
Education and Outreach | Community Service | Awards | Publications | People | ASR 2004 Home

National Center for Atmospheric Research University Corporation for Atmospheric Research National Science Foundation Annual Scientific Report - Home Atmospheric Chemistry Division Advanced Studies Program Atmospheric Chemistry Division Climate and Global Dynamics Division Environmental and Societal Impacts Group High Altitude Observatory Mesoscale & Microscale Meteorological Division Research Applications Program National Center for Atmospheric Research Scientific Computing Division