Cumulative Precipitation. Evapotranspiration. Cumulative Runoff. Imuris. Angostura. Angostura. Ixpalino. Bavispe River. Paso Nacori. Guadalupe. Moctezuma River. Cubil. LasPerlas. Guadalupe. 1. 2. 3. Huapaca. Novillo. 1. 1. 4. 1. 5. Novillo. 1. Aros-Papagochi River. 6.
Valle del Yaqui
The Extended University of Washington West-wide Hydrological Seasonal Forecast System: Covering Mexican Territory
1Chunmei Zhu, 1Francisco Munoz-Arriola, 1Adrew Wood, 2Ana Wagner-Gomez, 2Rene Lobato-Sanchez and 1Dennis P. Lettenmaier
1) Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, 98195
2) Instituto Mexicano de Tecnología del Agua, Jiutepec, Morelos, Mexico
Large fluctuations in precipitation streamflow are common in Imuris and Ixpalino, This variability is also observed in evapotranspiration. Precipitation begins to accumulate relatively early in the year, which explains the relatively homogeneous hydroclimatological regime. However, a high dispersion in the evapotranspiration and precipitation ensemble members may reflect poor skill of the ESP forecast in these basins due to the incidence of winter precipitation and corresponding high hydrologic variability. In the Ixpalino basin, on the other hand, the dispersion of the hydrological ensembles is greatest during the summer. We are also evaluating the method in the Oviachic sub basin of the Rio Yaqui basin. This basin is highly significant to the agricultural productivity of northwestern Mexico. This area is located in a semiarid domain and is strongly influenced by the North American Monsoon System. In this basin, the largest dispersion in the ensemble members occurs during the summer and late winter. One target of our work is to understand the skill of the hydrological forecast as the monsoon season is approaching. We are also evaluating, through linkage between the forecasts and a water management model, the impacts of the forecasts for water resources management.
Hydrologic forecasting in areas constrained by the availability of hydrometeorological records is a notable challenge in water resource management. Techniques from the University of Washington West-wide Seasonal Hydrologic Forecast system (www.hydro.washington.edu/forecast/westwide) for generating daily nowcasts in areas with sparse and time-varying station coverage are being extended from the western U.S. into Mexico. The primary forecasting approach consists of a nowcast system that utilizes gridded station data provided by Servicio Meteorológico Nacional (SMN), with a “fallback” option that uses NCEP weather forecast model nowcast fields (NDAS). Seasonal forecasts will be based on the NWS ensemble streamflow prediction method (ESP; essentially resampling of climatology) and on NCEP Coupled Forecast System (CFS) outputs. These in turn are being used to force the Variable Infiltration Capacity (VIC) macroscale hydrology model to produce streamflow ensembles. One-year lead time streamflow forecasts at monthly time step are being produced at a set of major river locations in Mexico. A case study is utilizing the streamflow forecasts, along with forecasts of reservoir evaporation, as input to the Simulation-Optimization (SIMOP) model of the Rio Yaqui system, one of the major agricultural production centers of Mexico. This is the first step in an eventual planned water management implementation over all of Mexico.
Hydrological Forecast Operation
The UW-West-wide Hydrological Forecast System produces hydrological nowcasts for the Western US and Mexico and is being expanded (in collaboration with Princeton University) to cover the Eastern US. as well Over the western U.S. portion of the domain, streamflow forecasts are made monthly (twice monthly in winter) at about 200 forecast points. The inclusion of Mexico will expand the forecast domain into Mexico, including watersheds characterized by the intensive use of water and lack of hydrological information. The extended domain includes 14 small basins characterized by relatively low natural streamflow, as well as one macro basin in which streamflow is intensively use for agricultural practices.
Ongoing work: SIMOP and the Rio Yaqui Hydraulic System
RESULTS and DISCUSSION
Forecast points within Mexico encompass different hydroclimatic regions, and water management considerations. In our initial evaluation, we evaluate parts of the implementation in three basins (Imuris, Ixpalino, and Las Perlas). For example, Imuris is located in an area that has frequently been affected by multiyear drought events, which have substantially impacted the region’s agriculture. On the other hand Las Perlas is located in southwestern Mexico, where anomalously high and continuous precipitation events produced flood ad land slides in the states of Chiapas and Tabasco in October of this year. Finally, Ixpalino is located the semiarid central part of Mexico at an altitude similar to Imuris but with an annual precipitation is intermediate between Imuri’s Las Perlas.
This project represents a first attempt to implement a seasonal hydrological forecast system over Mexico. Climatic and hydrological conditions contrast sharply with those in the western U.S., the location of most previous implementations of the ESP method. Hydrological forecasting over much of the domain is a challenge due to the highly variable precipitation regimes, and the extent to which hydrologic forecast skill can be achieved under these conditions is a research question that our implementation is expected to address.
Wood, A.W. and D.P. Lettenmaier, 2006: A testbed for new seasonal hydrologic forecasting approaches in the western U.S., Bulletin of the American Meteorological Society, 87(12), 1699-1712, doi:10.1175/BAMS-87-12-1699
Zhu C.M. and D.P. Lettenmaier, 2007:Long-term climate and derived surface hydrology and energy flux data for Mexico,1925-2004, Journal of Climate, 20, 1936-1946.
Note: See the author for other references.