Geoscience Reference
In-Depth Information
data by eliminating false echoes, using Doppler mode techniques to filter those echoes
caused by the interception beam (principal and/or secondary lobes) with the terrain. This
will give greater confidence to hydrologists that the data used were carefully treated before
feeding to their models.
Aiming to use the radar hydrological information with operational purposes, a short
hydrological forecast system should include the following components integrated
components: a) Automatic meteorological stations network (pluviographs); b) Weather
Radar; c) Satellite products and; d) Mesoscale numerical weather prediction model. The
main feature of each of these components is to provide real time and hours/days in advance
(forecast) rainfall data, which is a necessary condition for implementing an operational
hydrological system.
5. Weather forecast system
In most cases, the fire department response facing intense rainfall events over Mexico basin
is a merely emergency procedure. Its work would be greatly improved and lead to more
efficient use of human and material resources available by the city government by taking
advantage of weather information that is, diagnoses and forecasts of weather and climate.
Unfortunately, the information prepared by the National Weather Service lacks the detail
and quality required for making decisions as presented in general terms, without data, in
order to one can acquire confidence in the forecast. This problem is particularly severe when
it comes to prediction of severe storms considered as a danger to the water system in Mexico
City. Requirements to take the first steps in the right direction are the improvement of
surface measurement networks, radar and satellite information, forecasting deadlines to
produce hydrometeorological information useful in decision making for disaster prevention
and development of an early warning system that includes not just the danger or threat, but
also the vulnerability facing to severe weather.
Any centre that generates meteorological information for decision making is based on the
following required elements (Fig. 12):
1.
Data Collection
2.
Assimilation and display of information. Very short-term prognosis based on radar and
satellite estimates of rainfall and rain gauge information.
3.
Weather Forecast Systems
4.
Post-processing of weather forecasting in the short term to prepare products tailored to
user needs
5.
Scheme for submission of information to the user or decision maker, including an early
warning system useful for the Water System of Mexico City
6.
Seasonal climate forecasts for water management in the long run
Although all components are equally important, the main focus to be discussed here is
the radar network to be implemented in the system. Méndez et al. (2009) presented a
proposal for a new radar system for Mexico Valley based on precipitation analysis
estimated by the existing Cerro Catedral radar. They found an underestimation in the
amount of precipitation over the western mountains of the valley, at the foothills, while
rainfall rates tend to be overestimated over the eastern parts, resulting of the blockage
