Translated from Izvestiya An. Fizika atmosferi i Okeana

Abstract-An efficient technique for solving an inverse problem of remote sensing of atmospheric ozone at millimeter radio waves is described. The technique is based on an iteration scheme in which Tikhonov's method in the form of the principle of generalized residual is used at each step. A significant advantage of the method lies in the association of the regularization parameter and in the degree of smoothness of the solution with the total effective error. To increase the accuracy of the inverse-problem solution, a difference version of the technique is used. For this version of the technique based on data of thermal radio radiation of ozone molecules, the relative spectral behavior of brightness temperatures, but not their absolute values, are significant. Results of a numerical experiment modeling of ground-based atmospheric ozone observations within the spectral band centered at 142.2 GHz are given. Actual parameters, such as noise, operating frequencies, and spectra! resolution of the ozonometric instruments at the Lebedev Institute of Physics arc considered in computations. Results of the application of this technique to ozone observational data obtained in early 1996 over the Moscow region are given. The proposed method extends a class of problems, related to ecology and atmospheric physics, solvable with millimeter-wave-radiophysics methods

Radiative forcing from the 1991 Mount Pinatubo volcanic eruption

Volcanic sulfate aerosols in the stratosphere produce significant long-term solar and infrared radiative perturbations in the Earth's atmosphere and at the surface, which cause a response of the climate system. Here we study the fundamental process of the development of this volcanic radiative forcing, focusing on the serendipitous eruption of Mount Pinatubo in the Philippines on June 15, 1991. We develop a spectral-, space-, and time-dependent set of aerosol parameters for two years after the Pinatubo eruption using a combination of SAGE II aerosol extinctions and UARS-retrieved effective radii, supported by SAM II, AVHRR, lidar and balloon observations. Using these data we calculate the aerosol radiative forcing with the ECHAM-4 general circulation model (GCM) for cases with climatological and observed sea surface temperature (SST), as well as with and without climate response. We find that the aerosol radiative forcing is not sensitive to the climate variations caused by SST or the atmospheric response to the aerosols, except in regions with varying dense cloudiness. The solar forcing in the near infrared contributes substantially to the total stratospheric heating. A complete formulation of radiative forcing should include not only changes of net fluxes at the tropopause, but the vertical distribution of atmospheric heating rates and the change of downward thermal and net solar radiative fluxes at the surface. These forcing and aerosol data are available for GCM experiments with any spatial and spectral resolution. (orig.)Available from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Perspectives on the Future of Ice Nucleation Research: Research Needs and Unanswered Questions Identified from Two International Workshops

There has been increasing interest in ice nucleation research in the last decade. To identify important gaps in our knowledge of ice nucleation processes and their impacts, two international workshops on ice nucleation were held in Vienna, Austria in 2015 and 2016. Experts from these workshops identified the following research needs: (1) uncovering the molecular identity of active sites for ice nucleation; (2) the importance of modeling for the understanding of heterogeneous ice nucleation; (3) identifying and quantifying contributions of biological ice nuclei from natural and managed environments; (4) examining the role of aging in ice nuclei; (5) conducting targeted sampling campaigns in clouds; and (6) designing lab and field experiments to increase our understanding of the role of ice-nucleating particles in the atmosphere. Interdisciplinary teams of scientists should work together to establish and maintain a common, unified language for ice nucleation research. A number of commercial applications benefit from ice nucleation research, including the production of artificial snow, the freezing and preservation of water-containing food products, and the potential modulation of weather. Additional work is needed to increase our understanding of ice nucleation processes and potential impacts on precipitation, water availability, climate change, crop health, and feedback cycles.© 2017 by the author

Predicting the number of clouds droplets in the ECHAM GCM

In this paper a prognostic equation for the number of cloud droplets (CDNC) is introduced into the ECHAM general circulation model. The initial CDNC is based on the mechanistic model of Chuang and Penner [1995] providing a more realistical prediction of CDNC than the empirical method which was previously used. Cloud droplet nucleation is parameterized as a function of total aerosol number concentration, updraft velocity and a shape parameter, which takes the aerosol composition and size distribution into account. The total number of aerosol particles is obtained as the sum of marine sulfate aerosols produced from dimethyl sulfide, hydrophylic organic and black carbon, dust and sea salt aerosols. Anthropogenic sulfate aerosols only add mass to the pre-existing aerosols, but do not form new particles. The simulated annual mean liquid water path, column CDNC and effective radius agree well with observations as does the frequency distributions of column CDNC for clouds over oceans and the variations of cloud optical depth with effective radius. (orig.)Available from TIB Hannover: RR 1347(284) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman