Coastal-Urban Microclimates (2010-2012)

Weather and wind forecasting typically relies upon low-resolution computer simulations, with no more detail than a 12-kilometer grid.  Also, these model simulations virtually never incorporate urban features such as pavement and skylines.  As a result, they cannot accurately predict how temperature varies over city neighborhoods during a heat wave, nor can they always tell what direction wind will be blowing an atmospheric contaminant.  In the end, weather forecasters do an amazing job with mediocre weather models by using their long-term knowledge of what works for various situations and locations.

Air temperature measurements at 1:15 AM during a recent heat wave.  The 240 weather stations demonstrate how some neighborhoods around New York City were as much as 15 degrees warmer than rural areas.  Data credits given below.

Sometimes this isn’t good enough, so a goal of a research collaboration between our research group and collaborators at the Naval Research Laboratory and City College of New York was to push the boundaries of dealing with these shortcomings in atmospheric prediction.  Our research aimed to help improve prediction capabilities for weather and atmospheric transport, as well as the scientific understanding of urban weather features such as the urban heat island, which often keeps temperatures 10-15 degrees (F) warmer than rural areas at night, as shown above.  The influence of the ocean and sea breezes on weather is also captured much better by COAMPS than by most weather models.  Previous results and publications from similar research are summarized on Julie Pullen’s webpage.

We worked with the Navy’s Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) computer model, and using grids as high as 333 meters resolution.  For checking the model results with actual weather observations, we used the usual airport and city weather stations, maintained by NOAA, but also hundreds of civilian-run weather stations — all these are conveniently merged in City College’s NYC Met Net.

A student publication resulting from this research is:

Meir, T., Orton, P.M., Pullen, J., Holt, T., Thompson, W.T., Arend, M.F., 2013. Forecasting the New York City urban heat island and sea breeze during extreme heat events. Weather and Forecasting.  doi: 10.1175/WAF-D-13-00012.1.  webPDF

 

[Temperature figure data credits:  NOAA (NOS-PORTS, NWS-ASOS, NWS-HADS, Urbanet), Rutgers NJ Weather and Climate Network, APRSWXNET, AWS Convergence Technologies, Inc. (WeatherBug), and Weatherflow, via Mark Arend (NYCMetNet).]

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