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THERMODYNAMIC ANALYSIS OF BOREAL ECOSYSTEM R. Sandlerskiy, Yu.G.Puzachenko A.N. Severtsov Institute of Ecology and Evo lut ion RAS 119071, Moscow, Leninsky prospect 33, Russia e-mail: srobert_landy@mail.ru, puzak@orc.ru Transformat ion o f matter and energy in plant associat ions and their relat ionship wit h other parts of the ecosystem are being determined by the phys io logical processes in plants. Accordingly, to ident ify general patterns of ecosystem energy transformation, assessment of an energy balance components reflect ing the nature of phys io logical processes: photosynthesis, transpirat ion (of which carbon balance is evaluated), water and minerals exchange, is required. Assessment of the main energy variables for ecosystems is possible on the basis of informat ion-thermodynamic approach in which the ecosystem ­ is an open system, producing yield for self-maintenance on it s structure through the conversio n o f so lar energy. In do ing so, the distribut ion of energy absorbed by balance co mponents depends on the structure of the system that determines the nonequilibrium energy conversio n. In the information -thermodynamic approach essent ial co mponent in the transformat ion of so lar energy is exergy - the maximum work that a thermodynamic system may commit during its transit io n fro m the current state to the state of equilibrium wit h the environment (Jorgensen, Svirezhev, 2004). Exergy so met imes called syste m yield, it is the funct ion o f the distance between the current state of the system and thermodynamic equilibrium. Relat ing to ecosystems, exergy ­ part of absorbed solar energy, spend on bio logica l productivit y and evapotranspiration. The rest goes into the bound energy ­ energy transit ion in the heat flow and entropy, and in increment of internal energy ­ system energy accumulat ion wich in it s turn spend on maintenance o f interco mponent and interspecific interact ions, local cycles. Get estimation o f energy balance for the ent ire set of ecosystems based on ground-based measurements is virtually impossible. Such assessments are possible on the basis o f remote sensing data, which show the energet ic state of the Earth's surface at the time o f shooting in different spectral bands. Satellite measurements of reflected solar energy in relat ion to the solar constant allow the calculation o f solar radiat ion absorbed per unit surface. Heat channel allows to calculate the heat flow fro m the surface and its temperature. The development of remote sensing and instrument base allows to measure a wide range of ecosystems characterist ics: measurements are preformed direct ly in the field on transects wit h the regular testing step, and through remote sensing and digital models o f different relief. Ult imately, the combinat ion of complex ground and remote measurements in the study of energy balance should promote understanding of the interactio n mechanis m between relief, so il, vegetation and atmosphere at various hierarchical levels o f the landscape cover and create a basis for the development of models describing mesoclimate, as a result of landscape funct ioning and self-evo lut ion. The presented approach and implemented a set of measurements for the territory o f Central Forest Biosphere Reserve and its conservat ion zone ­ 32° 53 'E, 56° 46' N latitude. The landscape properties are in many respects unique (moraine ridge height with boreal spruce and co mplex spruce forest in a co mbinat ion wit h bogs, windfalls, cutover patches and fields), create a basis for comparison of properties of various types of a surface and their territorial co mbinat ions. The method of reflected solar energy est imat ion through Landsat satellite is described in the relevant manuals (Landsat 7 Science Data Users Handbook): values of this band are recalculated in reflected energy (watt/m2) flow, energy absorption value is the difference between inbound and reflected energy. On the basis of 6th band the heat flow is calculated (watt/m2) and act ive surface temperature (C). Calculat ion o f energy characterist ics of the territory conducted by the method proposed by S. E. Jorgensen and Y. M. Svirezhev (2004). Measurement of exergy on the basis o f remote sensing data carried out through assessment of distance between the real distribut ion o f energy absorption of so lar energy and equilibrium state, with a hypothetical absorption o f so lar energy in proportion to the distribut ion o f energy in the spectrum o f so lar constant. The degree o f realit y deviat ion fro m the equilibrium absorption spectrum is evaluated as Kulbak's entropy (a


measure of differences of two distribut ions and the parameter of open nonequilibrium thermodynamic systems). Bound energy is calculated as the product of heat flow and entropy o f reflected solar energy. Internal energy is estimated as absorbed energy minus exergy and bound energy. To assess the expenditure of energy used on bio logical production NDVI index was used. Thus for the studied territory through Landsat data with a spat ial reso lut ion o f 28.5 m, for the five dates (March, April, May, June, September) computed following energy characterist ics: the inco ming so lar energy, reflected solar energy, absorbed energy (radiat ion balance), albedo, entropy, exergy, entropy of reflected so lar energy, heat flow and temperature of active surface, bound energy, internal energy delta, the index o f productivit y. For the analysis o f the spat ial variation o f energy parameters their average values was calculated for flowing generalized landcover types: coniferous forests, deciduous forests, windfalls, meadows and agricultural land, high moors, and small man-made ponds (benchmarks maximum o f solar energy absorption). In general, analysis of the thermodynamic variables for different types o f ecosystems shows that the flow of energy absorbed by surface, is redistributed to several different mechanis ms and this redeplo yment depends on the structure of the system, which expressed through nonequilibrium. A nonequilibrium conversio n of solar energy in the first place determines the expenditure of energy on the bio logical production and has a litt le impact on exergy ­ the cost of energy for evaporation. Based on the method of principal co mponents invariance o f energy conversio n by a landscape in general and generalized t ypes of ecosystems is evaluated. Revealed energy variables wit h minimal variat ion in t ime, the maintenance of which can be defined as a target function o f ecosystem energy conversio n, for studied territory they are: energy absorption, exergy and heat flow. The abilit y to maintain basic invariants forms a regular range, which repeat the succession: "meadows ­ windfalls ­ deciduous forests ­ coniferous forests". Man-made objects ­ resident lands and roads have the lowest autoregulat ion abilit y. In contrast to the forest and grassland co mplexes, for the high moors internal and bound energy, heat flow and bio logical production are the most invariant. Bogs in contrast to the forest, carrying out mo isture transportation from the so il into the atmosphere, ho lding the high-heat ing level and conserve precipitat ion in a groundwater, while maintaining the level o f bio logical production, comparable to coniferous forests. Thus the nature and efficiency o f energy conversio n by a landscape cover is determined by its internal structure changing in the course of it self-development and succession shifts. On average invariant value assessed scale of regulat ion of heat flow through energy expenditure on evaporation, almost proportional to exergy in the vegetation season. Coniferous Forest in co mparison to pravifo liate decrease temperature by 1°C, relat ive to windfalls- nearly 2oC, and in relat ion to the treeless spaces ­ at 4oC, marshes are warmer than coniferous forests at an average o f 4.8oC. Thus, the analysis o f satellite imagery on the basis of thermodynamic approach allows evaluat ing o f the main features of a landscape thermodynamic variables spatial and temporal variat ion and their funct ional relat ionship, depended on the individual properties of the ecosystem. Research performed wit h financial support RFBR ­ projects 06-05-64937, 07-05-12021, as well as in the program o f fundamental research, Russian Academy o f Sciences "Biodiversit y and the dynamics of gene pools", subprogram "Biodiversit y "( 5.1.2). References 1. Jorgensen S.E., Svirezhev Y.M. 2004. Towards a Thermodynamic Theory for Ecological Systems. Langford Lane Kidlington. Oxford. Elsevier. 369 p 2. Landsat 7 Science Data Users Handbook / / http://ltpwww.gsfc.nasa.gov 3. Vernadsky V.I. 2004. Biosphere and Noosfere. Metro: Iris Press. 576 p. (in russian) 4. Sukachev V.N., Dylis N.V. 1964. Fundamentals of forest biogeocenology. Moscow: Science. 574 p. (in russian)