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Urban Heat Island Over Delhi Punches Holes in Widespread Fog in the Indo‐Gangetic Plains
Author(s) -
Gautam Ritesh,
Singh Manoj K.
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl076794
Subject(s) - air quality index , urban heat island , environmental science , geography , satellite , physical geography , climatology , meteorology , geology , aerospace engineering , engineering
Persistent and widespread fog affects several densely populated and agriculturally fertile basins around the world. Dense and polluted fog is especially known to impact transportation, air quality, and public health. Here we report a striking observation of holes in fog over urban areas in satellite imagery. The extent of fog holes appear highly correlated with city populations in fog‐prevalent regions of Asia, Europe, and the United States. We find the highest frequency and largest extent of fog holes over Delhi along with suppressed fog fraction, amidst increased fog occurrence over the Indo‐Gangetic Plains, based on 17 years of satellite data (2000–2016). This apparent urban heat impact is characterized in sharp urban‐rural gradients in surface temperatures and fog thickness. Urban heating seems to have already amplified the long‐term fog decline in Europe and the United States and should be assessed over regions undergoing urban expansion including India, where no previous linkages are reported between urban heating and fog.