The Mississippi Mesonet

Figure 11. Introduction and Objectives

Over the past five years, Jackson State University has taken a leading role in the development of a world-class mesoscale observing network in Mississippi for research, education, and operational use: The Mississippi Mesonet (White and Matlack 2005).

Broadly speaking a mesonet can be considered to be a network of automated weather observing stations whose spatial distribution facilitates near-real time description in between the standard “synoptic” observing stations of the National Weather Service (NWS) and Federal Aviation Administration (FAA). In many cases, they are characterized by improved temporal resolution and supplemental sensors compared to the synoptic network.

In partnership with the National Weather Service, a multi-institution steering committee has been promoting within Mississippi the anticipated benefits of a statewide mesonet for:

• Improved weather forecasts

• Improved hydrologic forecasts

• Emergency management

• Weather research and modeling

• Agriculture

• K-12 and higher education

In particular, special attention has been focused recently on the impacts of severe weather for public safety and the economy, as exemplified by the Central Mississippi outbreak of F3 tornadoes in April 2005 and the catastrophic devastation of Hurricane Katrina in 2006. Strong partnerships have naturally resulted with local and state emergency managers.

Figure 2This effort in Mississippi has operated within the context of recent NOAA (National Oceanic and Atmospheric Administration) initiatives for modernization of the cooperative observing system (“COOP”) to provide real time atmospheric data. These include the National Environmental Real-time Observing Network (NERON) and the National Integrated Drought Information System (NIDIS). Incorporation of Mississippi Mesonet data into NOAA’s Meteorological Assimilation Data Ingest System (MADIS), data are made routinely available for NWS forecasters and for potential assimilation into NOAA operational forecasting models. The mesonet also benefits NOAA by providing quality data for atmospheric research and as an opportunity for minority undergraduate students at JSU to gain experience with research instrumentation and data analysis.

2. Strategies

Using seed money from the NOAA Center for Atmospheric Studies (NCAS), JSU has been able to leverage various local, state, university, and federal funding sources to design and build the initial prototype network. During this Phase 1 of what is planned to be a comprehensive statewide network, an exhaustive survey of existing observing platforms within the state was made (White and Finney 2005), to consider the complementary roles of multiple networks and implications for modernization of the COOP network.
Figure 3The observing system that was selected blends the instrumentation and protocols of the Oklahoma Mesonet (Brock et al. 1995) and the Louisiana Agriclimatic Information System (LAIS) (Greenland 2005), with one-minute temporal resolution and sensor redundancy (to minimize sensor failure impacts). Real-time two-way communications are currently provided by spread spectrum radio, with consideration that the law enforcement telecommunications system (LETS) and/or MeteorBurst may be used at some sites in the future. The general categories of measurements being made include:

• Air temperature

• Wind

• Humidity

• Precipitation

• Pressure

• Solar radiation

• Soil moisture and temperature

Following guidance from NWS, a 20 mile grid was projected onto the state as a tool to plan for an eventual network of 120 stations evenly distributed around the state. Installation of the first five stations commenced from 2004 to 2006, to form the Phase 1 prototype network. During this time a critical partnership was formed with the National Center for Biodefense Communications at JSU. Also, extensive documentation describing site selection and installation procedures were developed.

Figure 43. Network Status

Renewal of JSU’s funding under NCAS has ensured continued operation of the network through 2011. By early 2008, the mesonet is expected grow to more than 15 stations, over half of which will be in the coastal region. Recent efforts at development of a comprehensive website http://jsumesonet.jsums.edu and data management scheme are continuing.

Challenges during Phase 1 primarily involved the limited resources available and the need to develop institutional support for the concept of the Mesonet. The difficulty of obtaining long-term access to observing sites that have with sufficient wind exposure and feasibility for spread spectrum radio transmission to a static internet site (such as public schools) remains. Although the state has been subjected to a large share of tropical cyclones and severe weather over the last two years, failures of mesonet observing equipment have been extremely rare. Most data interruptions have been due to internet connection problems and software issues. There has been a significant spin-up process for development of software, data management tools, and World Wide Web products.

4. Current Applications

Currently the mesonet data are used by NWS Weather Forecast Offices (WFOs) for forecasting and storm reports. On an hourly basis, data are integrated with NWS/FAA synoptic data to produce contour and streamline maps that are served via the website. Emergency managers use the data to provide local weather support in areas underserved by other networks. Recently, wind data from the Pascagoula site have been used by legal firms involved in settlement of hurricane insurance coverage suits in the wake of Hurricane Katrina. Development of online time series plots is underway, along with initiatives for data use in K-12 education.

Figure 5

Mississippi Mesonet data are currently being employed in research projects led by university and agency investigators. USDA scientists at the National Sedimentation Lab in Oxford and at the Plant Materials Lab in Coffeeville use the data for hydrology and crop studies. At JSU, various projects make use of the mesonet for studies on mesoscale modeling, the land/sea breeze circulation, nocturnal warming, and atmospheric dispersion. The University of South Alabama has supported the Mississippi Mesonet to provide in situ data for studies on interactions during hurricane landfall. And Mississippi State University intends to begin applying mesonet data to studies on land-surface interaction in severe storm environments.

Shortly after the first mesonet station was installed at Newton, surprisingly dramatic cases of nocturnal warming were noted that were not associated with frontal passages or convective activity. These “nocturnal warming events” (White 2005; White 2007) are being investigated in the context of regime transitions within the nocturnal boundary layer. Temperature increases of 2 to 5 degrees Celsius within a 15 to 30 minute period are often observed, usually with a return to the expected regime of gradual nocturnal cooling after a couple hours. Most cases are associated with nearly calm winds, which increase to speeds of 2 to 3 m/s during the warming.

5. Future Directions

As the mesonet expands, applications of the data to mesoscale modeling and phenomenological studies will grow. There are also initiatives for integration with GIS for emergency management, water quality applications, and atmospheric dispersion studies. Collocation of micrometeorological flux towers will provide opportunities for calibration and comparison of bulk turbulent energy fluxes. Collaboration with NCAS researchers is expected to consider approaches to use of three-dimensional variational (3dvar) assimilation of mesonet data into WRF, in particular to address short-term mesoscale weather impacts. There is interest in investigating application of a consensus approach to provide multi-sensor determination of proxy parameters for specialized applications (such as visibility for aviation or fire weather indices). JSU will also continue to expand its outreach to K-12 students and teachers and its training of undergraduate students in working with research instrumentation and data analysis.

Figure 6

Figure 7

6. References

Brock, F. V., K. C. Crawford, R. L. Elliott, G. W. Cuperus, S. J. Stadler, H. L. Johnson, and M. D. Eilts, 1995: The Oklahoma Mesonet: A technical overview. J. of Atmos. and Oceanic Tech., 12, 5-19.

Greenland, D. 2005: Climate variability and sugarcane yield in Louisiana. J. of Applied
Meteor., 44, 1655-1666.

White, 2005: Occurrence of nocturnal warming events at prototype sites of Mississippi Mesonet. Eos Trans. AGU, 86(18), Joint Assembly Supplement, abstract A13A-16.

White, L, and J. Finney, 2005: A descriptive survey of meteorological observing systems in Mississippi. J. of Miss. Acad. of Sci., 50, 213-223.

White, L. D., and E. Matlack, 2005: Initial implementation of a Mississippi Mesonet within the context of COOP Modernization. 15th Confer. on Applied Climatology, Savannah, GA.

White, 2007: Sudden nocturnal warming events in Mississippi. Manuscript submitted to National Weather Digest.