More frequent, more intense heat waves in store for New York City

City College of New York: Heat waves like those that baked the Northeast in July are likely to be more frequent and more intense in the future, with their effects amplified in densely built urban environments like Manhattan, according to climate scientists at The City College of New York (CCNY).

“Manhattan is subject to an urban heat island effect because its physical landscape is significantly different from the surrounding suburbs,” said Dr. Jorge Gonzalez, NOAA-CREST Professor of Mechanical Engineering in CCNY’s Grove School of Engineering. “This makes heat waves here more intense because Manhattan cannot cool off as readily as outlying areas.” Factors that contribute to the urban heat island effect include energy demand, air quality, asphalt surfaces and exhaust fumes.

Data collected by City College’s New York City Meteorological Network (NYCMetNet), indicate that during the first July heat wave overnight low temperatures ran 10 to 15 degrees (Fahrenheit) higher in Manhattan than in Long Island or in western New Jersey, while daytime highs were roughly the same. NYCMetNet is a networked system of several hundred ground-based sensors throughout metropolitan New York that gather weather and climate data.

High temperatures do not dissipate as quickly in Manhattan as in other areas because of the large amount of stored energy contained in its massive buildings, Professor Gonzalez explained. “While surrounding suburban and green areas may perceive the same maximum temperatures, the built regions will perceive them for longer periods of time.”

Part of NYCMetNet’s mission is to study and better describe urban climate and weather by using New York City as an outdoor laboratory to observe environmental processes in complex urban environments. “Our goal is to produce the next generation of physical models to describe climate and weather,” he continued. “Our vision is to show how cities modify climate and weather to scales that are relevant to people’s lives.”…

Temperatures in midtown Manhattan and the Upper West and Upper East Sides were hotter than those reported in Central Park, Washington Heights and Inwood. Map from CUNY website