Kirill Ya. Kondratyev

Global tropospheric ozone dynamics

An overview of the tropospheric ozone changes is presented focussing mainly on the tropospheric ozone precursors. The complexity of the problem is shown through the consideration of a great number of relevant substances, like nitrogen compounds, volatile organic compounds, peroxyacetyl nitrate, hydroxyl radical, carbon monoxide, alkyl nitrates. The up-to-date knowledge on the relevant numerical modelling is presented in Part II.

Global total ozone dynamics : Impact on surface solar ultraviolet radiation variability and ecosystems Part II: Dynamics of atmospheric chemical composition: The role of remote sensing Part I: Global ozone dynamics and environmental safety (ESPR 3/96, pp. 153-157).

Abstract (Part II)A review has been made recently studying global total ozone changes (including stratospheric and troposphere components), as well as biologically active surface solar ultraviolet (UV-B) radiation variations on the basis of satellite and conventional surface observations (Kondratyev and Varotsos, Part I). In the aforementioned review, relevant impacts on terrestrial and aquatic ecosystems, as well as on biochemical cycles and man, have been discussed. Special attention has been paid to the analysis of observed and potential impacts of enhanced UV-B radiation on biogeochemical cycles and the chemical composition of the atmosphere. In this context, possibilities remote sensing techniques applications aimed at obtaining more complete information on atmospheric concentrations of various trace gases determining the ozone content have been considered in the present paper.Abstract (Part I)An overview of the ozone issues is given including the following aspects: 1. The impact of tropospheric ozone on climate as a greenhouse gas (GHG), 2. Solar activity effects on TO and ozone concentration vertical profiles in both the troposphere and stratosphere (in cases of solar radiation absorption by the stratosphere, an unexpected problem arises via a coupling between processes of increased absorption due to “bursts” of solar activity and an enhanced destruction of ozone molecules due to the same increase resulting in weakening UV radiation absorption) and 3. Surface ozone concentration variations under conditions of polluted urban atmospheres which lead to episodes of photochemical smog formation (dangerous for human health).

Global total ozone dynamics

An overview of the ozone issues is given including the following aspects: 1. The impact of tropospheric ozone on climate as a greenhouse gas (GHG), 2. Solar activity effects on TO and ozone concentration vertical profiles in both the troposphere and stratosphere (in cases of solar radiation absorption by the stratosphere, an unexpected problem arises via a coupling between processes of increased absorption due to “bursts” of solar activity and an enhanced destruction of ozone molecules due to the same increase resulting in weakening UV radiation absorption) and 3. Surface ozone concentration variations under conditions of polluted urban atmospheres which lead to episodes of photochemical smog formation (dangerous for human health).

Estimation of Organic and Inorganic Matter in Inland Waters: Optical Cross Sections of Lakes Ontario and Ladoga

The high degree of optical complexity of inland water masses necessitates the development of models which consider the optical competitiveness of several co-existing aquatic components. A model is described which was developed to simultaneously estimate chlorophyll a, suspended mineral, and dissolved organic carbon concentrations from a single measurement of the subsurface volume reflectance spectrum in the optically complex waters of Lake Ontario. To estimate such aquatic concentrations requires a quantification, as a function of wavelength, of the amount of scattering and absorption that may be ascribed to a unit concentration of each aquatic component (i.e., the pertinent optical cross sections). Cross section spectra are presented for Lake Ontario and it is illustrated how such cross sections may be utilized in conjunction with directly-measured subsurface volume reflectance spectra and optimization analyses to extract the organic and inorganic components. Cross section spectra obtained in a similar manner for Lake Ladoga are also presented and compared to those of Lake Ontario. Similarities in absorption, but differences in backscattering cross section spectra for suspended inorganic matter were observed for the two lakes. Near-identical absorption and very similar backscattering cross section spectra suggest that Lakes Ontario and Ladoga are characterized by optically-comparable populations of chlorophyll-bearing biota.

Satellite Monitoring of Optically-Active Components of Inland Waters: An Essential Input to Regional Climate Change Impact Studies

Abstract Consistent with the climate change objectives of the IGBP is the need to remotely monitor and map both global and regional biological productivity over lands, oceans, and inland waters. Models and algorithms are currently being developed to infer aquatic primary production from near-surface chlorophyll concentration values determined from satellite sensors. Data from Lake Ladoga are utilized to illustrate that the algorithms currently being used to monitor near-surface chlorophyll concentrations in oceanic waters are inadequate when applied to water masses optically complicated by their proximity to land masses. Methodologies originally developed for retrieving simultaneous concentrations of chlorophyll, suspended minerals, and dissolved organic carbon from volume reflectance measurements of Lake Ontario are shown to display success in Lake Ladoga that could not be duplicated by six different oceanic chlorophyll retrieval algorithms. The principal requirements for water quality satellite monitoring are the cross sections of the optically-active components of the water body being remotely monitored. It is argued that, despite the spatial and temporal variability of such cross sections, their determination for principal water bodies should comprise both global and regional climate change studies.

Modelling the Radiometric Color of Inland Waters: Implications to a) Remote Sensing and b) Limnological Color Scales

Utilizing a bio-optical model previously developed for Lake Ontario, the responsiveness of chromaticity coordinates (X, Y, Z), dominant wavelength (λdom), and associated spectral purity (p) to the abundance of color-producing agents (CPA) residing within the Lake Ladoga water column was determined. CPA considered were phytoplankton (chl), suspended minerals (sm), and dissolved organic carbon (doc). Waters that contain simultaneously low concentrations of chl, sm, and doc are shown to appear blue to turquoise in color (472–500 nm). Highly turbid waters (i.e., waters containing high concentrations of chl and/or sm) with low concentrations of doc are shown to display colors ranging from green to brown (> 500 nm). Waters with large concentrations of doc, irrespective of turbidity, are shown to be invariably brownish (560–570 nm). With increasing CPA content, X, Y, and Z (and, consequently, λdom) asymptotically approach constant limit values. An “end-point” dominant wavelength at about 572 nm appears to be intrinsically characteristic of all natural waters. It is shown that when one or more CPA exceeds a critical concentration, the spectral purity p asymptotically approaches values in the range 0.35 to 0.45 for all waters (exceptive of those containing solely chl in the restricted concentration range < 0.5 μg/L). Optical distinctiveness, particularly with respect to indigenous doc, of natural waters, while impacting the spectral purity of the “end-point” radiometric color, does not produce a comparable impact on the “end-point” color itself. This work reinforces the restrictive application of chromaticity analyses to the remote sensing of binary aquatic systems comprised of water plus one CPA. It also illustrates that neither panchromatic nor two-channel ratio images can provide unambiguous inference of water quality parameters. Correspondence between radiometric water color descriptors (X, Y, Z, λdom, and p) and water color scales traditionally used in limnology is established, illustrating that the platinum-cobalt scale would be most appropriate for assessing waters that were radiometrically yellow, provided that the yellow hue were not invariably attributed to doc.

Application of a Global Model to the Study of Arctic Basin Pollution

The introduction of man-made radionuclides, heavy metals and oil hydrocarbons into the Arctic basin has been, of international concern since the 1992 release of information on Soviet dumping of nuclear reactor and solid industrial waste. The purpose of this chapter is to develop and to investigate a simulation model of the pollution dynamics in the Arctic basin. There are many observational and theoretical results giving estimates of the growing dependencies between the pollution dynamics in the World Ocean and the state of the continental environment.

Combined application of remote sensing and in situ measurements in monitoring environmental processes

Combined use of remote sensing in the visible, infrared and microwave spectral regions, direct in situ measurements and model numerical experiments makes it possible to study inland water bodies as elements of water bodycatchment-atmosphere-systems with good spatial and temporal resolution. In this paper examples are presented of the remote sensing methods developed for detection of hydrodynamics of large water bodies (e.g. frontal and upwelling zones, internal waves, warm and cold surface layers), monitoring of chlorophyll concentration, suspended minerals and dissolved organic matter (DOM) in lakes, mapping of shallow water zones, wetlands and landscape structures, monitoring of ecological condition and changes of drainage basins, and studying the state of the atmosphere over lakes and catchment areas.

Volcanic Eruptions and Climate Change

The environmental impact of the 1991 Mt. Pinatubo volcano eruption in the stratosphere, as well as relevant consequences for global climate change and ozone layer dynamics have been discussed, with special emphasis on the possibility of identifying the volcanic climatic signal (VCS). The combined results of ground-based, balloon, aircraft, and satellite monitoring of the volcanic cloud propagation, and the scale of ejections have been considered and compared with similar data for other explosive volcanic erutpions to show that the Mt. Pinatubo eruption has doubtless been the most powerful one, especially with regard to the emissions of sulphur-containing gases. The perspectives of future satellite monitoring of volcanic eruptions have been briefly discussed. It has been emphasized that the results of numerical modelling aimed at the assessment of climate change due to eruptions are controversial. It has been shown that it is difficult to identify VCS because of coupling between various climate-forming processes (the El Nino/Southern Oscillation phenomenon, and the Quasi-Biennial Oscillation in the Stratosphere being of special significance).

Global environmental change and the World Ocean

To increase the reliability of assessing the role of the World Ocean in the global carbon cycle, a more detailed description is needed of the production processes in the ocean ecosystems. Along with the physical and chemical processes of transformation and motion of carbon in the ocean medium, the biological processes play an important role. In particular, phytoplankton, like the nutrient elements, assimilates dissolved CO2 from the salt water. As a result, an organic substance is formed that partially goes into the nutrient chains of the trophic pyramids of the World Ocean and partially descends to bottom sediments. A totality of all processes of carbon motion in the ocean medium creates a gradient of CO2 concentration between surface and deep waters (Klubov et al., 2000; Raupach et al., 2001; Rau and Caldeira, 2002). Therefore, a study of the structure and functioning of the ocean ecosystems becomes one of the most important and rapidly developing directions of marine biology. Its various aspects are being developed in many countries within the framework of the International Biological Programme. In particular, the international programme JGOFS (Joint Global Ocean Flux Study) is dedicated to a study of biochemical processes in the ocean to obtain a deeper knowledge of the response of the ocean to external forcings. One of the goals of the studies is to obtain a possibility to predict the system’s behaviour as a result of changes of some of its parameters. However, due to the unique nature and broad spatial extent of the World Ocean, it is difficult to quantitatively estimate all the elements of the system at different moments of development and in different regions of the World Ocean and, moreover, to assess the effect of their change on the functioning of the system on the whole. With this aim in view, regular expeditions are organized, databases of satellite monitoring of the World Ocean basins are accumulated, and methods are developed for using the model approach for these purposes. Of course, an accuracy of assessing the role of water ecosystems in global changes of greenhouse gas (GHG) cycles in general depends much on a thorough and accurate description of photosynthesis as a function of the environmental parameters and especially with consideration of its seasonal variations (Seibel and Walsh, 2001; Thebault and Rabouille, 2003).