Thomas Holzer-Popp

Short Range Direct and Diffuse Irradiance Forecasts for Solar Energy Applications Based on Aerosol Chemical Transport and Numerical Weather Modeling

Abstract This study examines 2–3-day solar irradiance forecasts with respect to their application in solar energy industries, such as yield prediction for the integration of the strongly fluctuating solar energy into the electricity grid. During cloud-free situations, which are predominant in regions and time periods focused on by the solar energy industry, aerosols are the main atmospheric parameter that determines ground-level direct and global irradiances. Therefore, for an episode of 5 months in Europe the accuracy of forecasts of the aerosol optical depth at 550 nm (AOD550) based on particle forecasts of a chemical transport model [the European Air Pollution Dispersion (EURAD) CTM] are analyzed as a first step. It is shown that these aerosol forecasts underestimate ground-based AOD550 measurements by a mean of −0.11 (RMSE = 0.20). Using these aerosol forecasts together with other remote sensing data (ground albedo, ozone) and numerical weather prediction parameters (water vapor, clouds), a prototype ...

Possible contribution of satellite measurements to monitoring of air pollution in European cities and their surrounding areas for health services

Today there is broad agreement that populations health is significantly affected by influences from the polluted environment. Among the most tremendous consequences are allergies, skin cancer, and deseases of the respiratory tract. As a result of increasing frequence of such health problems health services started to initiate so-called environmental ambulances where patients get proper advice and treatment, especially in densely populated areas with severe air pollution problems. It turned out that the work of such ambulances can be strongly supported by delivering information on environmental conditions such as tropospheric ozone smog, aerosol particles and UV irradiance in near-real time. In such a way the medical staff is supplied with proper knowledge on the occurence of pollution events and their spatial distribution and detailed nature. The German Remote Sensing Data Center (DFD) receives data of different sensors on various satellite platforms and processes them into products of tropospheric ozone, the optical thickness and type of aerosol particles and UV intensity on 1-40 km grids. Satellite retrieved information itself can thus be a tool to monitor air quality and will directly be used by the environmental ambulance and other public health services. Furthermore, DFD extracts information about land use/land cover from its operational processing chains allowing the characterisation of ground pixels in terms of emissions of biogenic volatile organic compounds (BVOC) into the air. Air Pollution VIII, C.A. Brebbia, H. Power & J.W.S Longhurst (Editors)

Benefits and limitations of the synergistic aerosol retrieval SYNAER

Air pollution by solid and liquid aerosol particles suspended in the air is one of the major concerns in developed countries because of potential health impact of increasing numbers of nano-particles in particular from diesel engines (see, e.g., [2002] and [2004]), as well as in developing countries with their high particle concentrations in the air. Furthermore, windblown dust can also act as carrier for long-range transport of diseases, e.g., from the Sahara to the Caribbean or Western Europe [Pohl, 2003], or even around the globe [Prospero et al., 2002]. Also well known in principle are direct (by reflecting light back to space) and several indirect (e.g., by acting as cloud condensation nuclei) climate effects of aerosols, although large uncertainties exist in the exact values of the forcing [IPCC, 2007]. Finally, the highly variable atmospheric aerosol load has a major impact on satellite observations of the Earth’s surface that need to be atmospherically corrected for quantitative analysis and on the solar irradiance which is exploited in solar energy applications (aerosols are the determining factor in clear-sky conditions). In all these cases an estimation of the type of aerosols is required for an accurate quantitative assessment. For example, [2002] point out, that the absorption behavior of particles (mainly soot and minerals) needs to be known in order to assess their total direct and indirect climate effects. This is because strongly absorbing particles can regionally reverse the sign of the aerosol direct forcing from cooling to heating or suppress cloud formation. Therefore, attempts have been made to extend satellite aerosol retrieval beyond observation of the spatial-temporal distribution patterns to estimate the type of aerosols.

Retrieval of aerosol properties over land and ocean by exploiting the synergy of GOME and ATSR-2 data

Satellite observation of aerosols is limited to the oceans or UV absorbing aerosols. To overcome these restrictions the new synergetic aerosol retrieval method SYNAER (synergetic aerosol retrieval) was developed. SYNAER delivers boundary layer aerosol optical thickness (BLAOT) and type over both land and ocean. The high spatial resolution of the radiometer ATSR-2 permits cloud detection, BLAOT calculation over automatically selected dark pixels and surface albedo correction for a set of different boundary layer aerosol mixtures. After spatial mapping and integration of ATSR-pixels to pixels of the spectrometer GOME these parameters are used to simulate spectra for the same set of different aerosol mixtures. A least square fit of these spectra to the measured GOME spectrum delivers the BLAOT value and the aerosol mixture. First case studies using ground based sun-photometer measurements show a good agreement.