Spatiotemporal Patterns of Solar and UV Irradiances in the Contiguous United States

摘要

BACKGROUND: Skin cancer is the most common type of cancer in the United States. The majority of skin cancer is caused by overexposure to ultraviolet (UV) light. The National Environmental Public Health Tracking Program (EPHT) at CDC has collaborated with partners to develop and disseminate county-level daily UV irradiance (2005 to 2015) and total solar irradiance (1991 to 2012) data for contiguous United States. The objectives of this study are to present our methods for generating and evaluating UV and solar irradiance datasets, and to describe their spatial distribution and temporal trend. METHODS: UV dataset was derived based on measurements from Ozone Monitoring Instrument (OMI) aboard NASA's Aura spacecraft. For evaluation, erythemally weighted UV irradiance was compared with ground observations at 27 sites. Solar irradiance were extracted from National Solar Radiation Data Base (NSRDB) and SolarAnywhere data. In addition, we conducted regression analysis to understand long-term trends at both the national level and by state for UV and solar irradiances. RESULTS: When comparing UV irradiance from OMI with ground observations, the correlation coefficients range from 0.66 to 0.93 with an average of 0.86. Solar and UV irradiances both had a latitudinal gradient increasing towards the South, and a longitudinal gradient increasing towards the West. The lowest state averages occurred in Vermont for solar irradiance and Maine for UV irradiance. The highest state averages were both in Arizona. National annual average solar and UV irradiances both increased significantly over the years included in this analysis. We made both datasets available to the public through CDC's EPHT network. CONCLUSIONS: The UV dataset is currently the only publicly available, spatially resolved long-term UV radiation dataset covering the contiguous United States based on latest satellite remote sensing technique. These datasets allow for improved characterization of UV and sunlight exposure.