Kolmogorov complexity spectrum for use in analysis of UV-B radiation time series

We have used the Kolmogorov complexity and sample entropy measures to estimate the complexity of the UV-B radiation time series in the Vojvodina region (Serbia) for the period 1990-2007. We defined the Kolmogorov complexity spectrum and have introduced the Kolmogorov complexity spectrum highest value (KLM). We have established the UV-B radiation time series on the basis of their daily sum (dose) for seven representative places in this region using (i) measured data, (ii) data calculated via a derived empirical formula and (iii) data obtained by a parametric UV radiation model. We have calculated the Kolmogorov complexity (KL) based on the Lempel-Ziv Algorithm (LZA), KLM and Sample Entropy (SE) values for each time series. We have divided the period 1990-2007 into two sub-intervals: (a) 1990-1998 and (b)1999-2007 and calculated the KL, KLM and SE values for the various time series in these sub-intervals. It is found that during the period 1999-2007, there is a decrease in the KL, KLM and SE, comparing to the period 1990-1998. This complexity loss may be attributed to (i) the increased human intervention in the post civil war period causing increase of the air pollution and (ii) the increased cloudiness due to climate changes.Comment: 10 pages, 1 figure, 1 table. arXiv admin note: substantial text overlap with arXiv:1301.2039; This paper has been accepted in Modern Physics Letters B on Aug 14, 201

An Approach for Calculation of Turbulent Transfer Coefficient for Momentum inside Vegetation Canopies

A method for calculating the profile of turbulent transfer coefficient for momentum inside a vegetation canopy for use in land surface schemes is presented. It is done through the following steps. First, an equation for the turbulent transfer coefficient for momentum inside a vegetation canopy using the “sandwich” approach for its representation is derived. Second, it is examined analytically to determine whether its solution is always positive. Third, the equation for the turbulent transfer coefficient is solved numerically, using an iterative procedure for calculating the attenuation factor in the expression for the wind speed inside a vegetation canopy that is assumed to be a linear combination of an exponential function and a logarithmic function. The proposed method is tested using 1) the observations for the wind profiles in a Japanese larch plantation and a pine forest and 2) the outputs for surface fluxes and total soil water content obtained by the Land–Air Parameterization Scheme (LAPS) with the forcing data and observations in a soybean field at the Caumont site in France during the 1986 growing season. Also, a test is performed that compares the proposed method with the method for calculating the turbulent transfer coefficients for momentum inside a vegetation canopy commonly used in land surface schemes

A Short Description of the First Serbian UV Index Model

A numerical model called “NEOPLANTA” for estimating solar UV irradiance and UV index under cloud-free conditions is being developed and tested at the University of Novi Sad in Serbia. In this paper, the model features, calculation procedure, and input parameters are described. Effects of the absorption of UV radiation by O3, SO2, and NO2 and absorption and scattering by aerosol as well as the air molecules in the atmosphere are included. The performance of the model has been tested with respect to its capability of UV index, which is a weighted integral between 280 and 400 nm of the solar irradiance reaching the ground. For this test 10-day data measured during the spring and summer in 2003, 2004, and 2005 are used. Data are recorded by the Yankee UVB-1 biometer located at the Novi Sad university campus (45.33°N, 19.85°E; 84 m MSL). Error analyses indicate that the modeled values agree well with the observation

Randomness representation in turbulent flows with bed roughness elements using the spectrum of the Kolmogorov complexity.

One feature of turbulent flow in relation to randomness is quantified. Experimental data from a turbulent flow collected in a laboratory channel with bed roughness elements of different densities are used. An analysis based on a classical turbulence statistics is performed, using a simple empirical model for estimating the relative sizes of mixing lengths representing the typical scale of an eddy in the corresponding surface layer, to describe the turbulence in terms of irregular or random flow. Instead of such description a quantification of the turbulence flow using measures based on the spectrum of the Kolmogorov complexity (KC) is proposed

Climate change effects and UV-B radiation in the Vojvodina region, Serbia under the SRES-A2

In this article we considered the extreme temperatures, precipitation and UV-B radiation in Vojvodina region, Serbia. We describe the actual climate conditions for the period 1981-2007 and applied a dynamic downscaling technique using the EBU-POM regional coupled climate model under the SRES-A2 scenario to assess the changes for the period 2021-2100. The results indicate that a warmer and drier climate in the Vojvodina region can be expected at the end of the century. Projection of climate indicates to a strong increase in the mean annual minimum temperatures, and much smaller increase in the mean annual maximum temperatures. The increase of both extreme temperatures is predicted to be the highest in the winter and the lowest in the summer. Mean annual precipitation is projected to increase toward the end of the first half of the 21st century and to decrease for the last 30 years of the 21st century. Precipitation amount will be the highest during the winter and spring. The model simulations show that, by the end of this century, annual mean UV-B dose will recover by 5.2%. Recovery will be faster in the first half of the 21st century and more slowly later on. The UV-B doses recovery is expected to be the highest during the autumn and spring