The University of South Alabama Mesonet: Challenges and opportunities for the future

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Monday, 18 January 2010
Sytske Kimball, University of South Alabama, Mobile, AL

Handout (1.6 MB)

The University of South Alabama (USA) Mesonet was established in 2005 with the construction of 2 stations. Since that time, the network has grown to include 14 currently operational sites with 12 more to become operational by October 2009. The main purpose of the mesonet is to monitor landfalling tropical storms and hurricanes, hence, most stations are installed in coastal counties and the line of counties north of the coastal counties. Meteorological data collected are precipitation, temperature at 4 levels, soil surface temperature, relative humidity at 2 levels, wind speed and direction at 2 levels, total solar radiation and photosynthetically active radiation, atmospheric pressure, vertical windspeed, and soil moisture and temperature at 5 depths. Since our major goal is monitoring landfalling hurricanes, our stations are robust in construction and feature redundant sensors. Data are disseminated every 5 minutes all year round to serve a multitude of purposes including weather forecasting, education, and research. The mesonet stretches about 325 km in an east-west direction, across 3 states. The north-south dimension ranges from about 100 km at the western end to about 30 km in southeast Alabama north of the Florida Panhandle. The spacing between stations ranges from 5.4 to 55.6 km with an average of about 30 km. Stations are visited at least once per month for general maintenance and instrument repair, cleaning, and inspection. Instruments are calibrated once per year. Near real-time, meta, and archived data are available on a website and data is also streamed into NOAA's Meteorological Assimilation Data Ingest System (MADIS) to reach as wide an audience as possible. The team keeping the operation afloat currently consists of 5 full-time employees and one PI/director.

Statistical analyses using our redundant sensors show that our data pass internal consistency checks and obey basic physical laws. Differences between temperature, humidity, radiation, precipitation, and wind measured by different sensors and/or at different positions at any given site all fall within acceptable limits. Sensor redundancy allows for 1) the availability of extra sensors in the case of sensor failure during severe weather and 2) the ability to perform a large number of internal consistency checks for quality control (QC) purposes. The highest priority task in the very near future for the USA mesonet will be to implement an automated QC system. Archived data will be used when setting QC thresholds. For increased refinement of QC range-, internal consistency-, and buddy- tests, data will be stratified by season and/or time of day.

In addition to the network of land-based observing sites NOAA's Atlantic Oceanographic and Meteorological Laboratory in Miami Florida deploys three Nortek Acoustical Wave and Current (AWAC) instruments south of Mobile Bay, AL every hurricane season since 2007. These AWACs record sea surface height, directional wave spectrum, subsurface ocean current profiles and bottom temperature. Connecting these observations to USA mesonet observations will form an integrated picture of a landfalling hurricane or fronts moving on or off shore. Such a data set has significant value for fine tuning models that predict storm surge and thus enable emergency managers to make life and property saving decisions in a timely manner.

The major challenge faced by the USA mesonet and many other similar operations is the question of continued funding after our existing sources expire. With the extended use of our data and the availability of data-derived customer specific products, local, state, federal, and private funding will be actively pursued in order to maintain this important service of providing severe weather forecasts and warnings, education, and climate records for the people of the north-central Gulf Coast. We are hopeful that the Network of Networks proposed in the national Academy of Science report “Observing weather and climate from the ground up” will provide not only guidance via an overarching national strategy, but also funding for maintenance, operation, and personnel.