Variability of surface characteristics and energy flux patterns of sunn hemp (Crotalaria juncea L.) under well-watered conditions

There is not much information in the literature about the energy partitioning and micrometeorological features of sunn hemp. Therefore, in this study, the variations in the energy-balance components and plant characteristics such as aerodynamic and surface conductance, crop coefficient, albedo, short- and long wave down- and upward radiation have been measured and estimated for the time period from August to October 2004 over an irrigated sand field at the Arid Land Research Center in Tottori, Japan. The Bowen ratio energy-balance method was used to calculate the partitioning of heat fluxes of sunn hemp. The Bowen ratio values at the first growing stages in August were found to be higher than the Bowen ratio values at the latest growing stages in September and October because of the heavy rain and high soil-water content. The daytime averaged Bowen ratio was 0.19. During the measurement period, the daytime average net radiation, and soil, latent and sensible heat fluxes were approximately 231, 28, 164, and 39 W m^–2, respectively. The net radiation and soil heat flux showed decreasing trends from the beginning to the end of the experiment period due to the atmospheric and crop growth conditions. The daytime averages of aerodynamic and surface conductance for sunn hemp were around 31 and 17 mm s^–1, respectively. Also, the daytime average albedo of sunn hemp was around 19%. Finally, the high precipitation amount due to typhoons, high soil-water content, low available energy and low vapor-pressure deficit lead to decreasing trend of the energy fluxes during the generative phase of sunn hemp.     

An application of network design procedures for redesigning Kizilirmak River basin raingauge network,Turkey

ABSTRACT

Recently developed rainfall network design techniques are discussed and compared. Present day hydrological studies require high levels of accuracy from collected data. Also, scientists need to know the degree of accuracy of the information they use. The existing rainfall network in the Kizilirmak basin must be redesigned in order to meet the required level of accuracy preset by rainfall data users. The three following techniques were applied: optimum interpolation procedure which is a flexible method; variance of mean areal rainfall; and the analysis of variance. The existing network of 52 gauges is redesigned so that the network will have an average root mean square error (rmse) of ? 32 mm and the percentage of the area with rmse > 36 mm is limited to 10%. It is found that the proposed criteria are satisfied by a network of 53 gauges of which eight were newly established and seven of the existing ones removed.     

Rainfall distribution function for Libya and rainfall prediction

Abstract

Monthly rainfall amounts are distributed according to different frequency distribution functions in different parts of the world. However, in extremely arid regions gamma probability distribution functions are most often found to fit the existing data well. Libyan monthly rainfall distributions are found to abide by gamma probability distribution function which is confirmed on the basis of chi-square tests. Almost all the rainfall sequences recorded for at least the last 20 years in Libya are investigated statistically and gamma distribution parameters are calculated at existing stations. The shape and scale parameters are then regionalized and hence it becomes possible to find the parameter values at any desired location within the study area and then to generate synthetic sequences according to the gamma distribution. Predictions of 10, 25, 50 and 100 mm rainfall amounts are achieved by this probability function.     

Modified hydrograph method for arid regions

There is a real need for more research on regionalization of flood estimation methods in arid zones. Such estimations are important because reliable long‐term storm rainfall and corresponding runoff measurements are commonly unavailable. This is the situation in many parts of the Kingdom of Saudi Arabia. Hence, it is necessary to develop a new approach, one that suits the conditions found in the Kingdom, which depend on available, but incomplete measurements and catchment morphological features. In this paper, a modified methodology based on the classical Snyder approach is proposed and it is referred to as the Saudi Geological Survey (SGS) approach in order to reflect works of this kind within the Survey. The basis of the methodology has two phases, namely, logical and empirical. The former phase is valid for any part of the world whether humid or arid, but the latter phase is location specific, which in the case of this paper, is the Arabian Peninsula. The application of the methodology is presented for Wadi Baysh, a major wadi in the south‐western part of the Kingdom. Furthermore, a synthetic unit hydrograph (UH) methodology based on a Gamma distribution function is also presented with applications to some of the Wadi Baysh sub‐basins. For this purpose, a dimensionless UH has been obtained, which is special for the area. Copyright © 2007 John Wiley & Sons, Ltd.     

A New Natural Secondary Reference Material for Garnet U-Pb Dating by TIMS and LA-ICP-MS

Gem quality andradite-rich garnet (IUC-1), obtained from the Miocene trachyte dome near Ankara city (Turkey), has been identified as a potential natural secondary reference material for U-Pb dating. In this study, U-Pb dating was performed in five different laboratories using isotope dilution TIMS and laser ablation ICP-MS to determine the homogeneity of euhedral garnet crystals. The U-Pb ID-TIMS data for IUC-1 yielded ²⁰⁷Pb/²³⁵U and ²⁰⁶Pb/²³⁸U ages of 20.9 ± 0.4 and 20.6 ± 0.8 Ma respectively, and these values are consistent with U-Pb LA-ICP-MS analyses, in which different garnet crystals yielded ages of 20.8 ± 0.1, 20.7 ± 0.1, 20.7 ± 0.2 and 20.2 ± 0.1 Ma. An andradite (IUC-2) from the Serçeören wollastonite skarn (Turkey) can be used as a secondary reference material provided detailed imaging of the crystals is undertaken. ID-TIMS data yielded ²⁰⁷Pb/²³⁵U and ²⁰⁶Pb/²³⁸U ages of 20.4 ± 0.4 and 20.9 ± 1.0 Ma respectively, and yielded U-Pb ages on different grains of 20.5 ± 0.1, 20.7 ± 1.0, 20.8 ± 1.7 and 20.9 ± 1.6 Ma. The assigned weighted mean age of IUC-1 (20.4 ± 0.5 Ma, 2s) is proposed as a 2023 reference value. IUC-1 garnet is expected to contribute significantly to rapidly developing garnet geochronology in the near future.     

A fault zone cause of large amplification and damage in Avcılar (west of Istanbul) during 1999 Izmit earthquake

Twenty seven buildings collapsed and 2076 buildings were heavily damaged during 17 August 1999 Izmit Earthquake in Avc?lar (west of Istanbul), which is nearly 100 km from the epicenter of the earthquake. The geology of Avc?lar consists of Upper Miocene poorly bounded conglomerate and sandstone (Çukurçe?me formation), claystone with sandstone and limestone interbedding (Güngören member) and limestone with sandstone and claystone interbedding (Bak?rköy formation). Lithological and geotechnical parameters of these formations in Avc?lar are not different from non damaged parts of the western Istanbul such as Zeytinburnu, Bak?rköy and Beylikdüzü, but these formations were cut by several faults in the damaged area. Collapsed and damaged buildings are located on this fault zone. Thus, cause of large amplification and damage in Avc?lar might be related with this fault zone because the fault zone behaves as a waveguide trapping seismic energy.