资源环境科技发展态势分析平台

Satellite data from the Ozone Measuring Instrument (OMI) and Earth Polychromatic Imaging Camera (EPIC) are used to study long-term changes and global distribution of UV erythemal irradiance E(zeta, phi, z, t) (mW m(-2)) and the dimensionless UV index E/(25 m Wm(-2)) over major cities as a function of latitude longitude zeta, altitude phi, and time t. Extremely high amounts of erythemal irradiance (12 < UV index < 18) are found for many low-latitude and high-altitude sites (e.g., San Pedro, Chile, 2.45 km; La Paz, Bolivia, 3.78 km). Lower UV indices at some equatorial or high-altitude sites (e.g., Quito, Ecuador) occur because of persistent cloud effects. High UVI levels (UVI > 6) are also found at most mid-latitude sites during the summer months for clear-sky days. OMI time-series data starting in January 2005 to December 2018 are used to estimate 14-year changes in erythemal irradiance Delta E, total column ozone Delta TCO3, cloud and haze transmission Delta C-T derived from scene reflectivity LER, and reduced transmission from absorbing aerosols Delta C-A derived from absorbing aerosol optical depth tau(A) for 191 specific cities in the Northern Hemisphere and Southern Hemisphere from 60 degrees S to 60 degrees N using publicly available OMI data. A list of the sites showing changes at the 1 standard deviation level 1 sigma is provided. For many specific sites there has been little or no change in E(zeta, phi, z, t) for the period 2005-2018. When the sites are averaged over 15 degrees of latitude, there are strong correlation effects of both short-and long-term cloud and absorbing aerosol change as well as anticorrelation with total column ozone change Delta TCO3. Estimates of changes in atmospheric transmission Delta C-T (zeta, phi, z, t) derived from OMI-measured cloud and haze reflectivity LER and averaged over 15 degrees of latitude show an increase of 1.1 +/- 1.2 % per decade between 60 and 45 degrees S, almost no average 14-year change of 0.03 +/- 0.5 % per decade from 55 degrees S to 30 degrees N, local increases and decreases from 20 to 30 degrees N, and an increase of 1 +/- 0.9 % per decade from 35 to 60 degrees N. The largest changes in E(zeta, phi, z, t) are driven by changes in cloud transmission C-T. Synoptic EPIC radiance data from the sun-lit Earth are used to derive ozone and reflectivity needed for global images of the distribution of E(zeta, phi, z, t)) from sunrise to sunset centered on the Americas, Europe-Africa, and Asia. EPIC data are used to show the latitudinal distribution of E(zeta, phi, z, t) from the Equator to 75 degrees for specific longitudes. EPIC UV erythemal images show the dominating effect of solar zenith angle (SZA), the strong increase in E with altitude, and the decreases caused by cloud cover. The nearly cloud-free images of E(zeta, phi, z, t) over Australia during the summer (December) show regions of extremely high UVI (14-16) covering large parts of the continent. Zonal averages show a maximum of UVI = 14 in the equatorial region seasonally following latitudes where SZA = 0 degrees. Dangerously high amounts of erythemal irradiance (12 < UV index < 18) are found for many low-latitude and high-altitude sites.

High levels of UVI are known to lead to health problems (skin cancer and eye cataracts) with extended unprotected expo- sure, as shown in the extensive health statistics maintained by the Australian Institute of Health and Welfare and the United States National Institute of Health National Cancer Institute.