Vulnerability of Bulgarian agriculture to drought and climate variability with focus on rainfed maize systems     

Z.?Popova  M.?Ivanova  D.?Martins  L.?S.?PereiraEmail author  K.?Doneva  V.?Alexandrov  M.?Kercheva 《Natural Hazards》2014,74(2):865-886

Bulgarian agriculture is affected by droughts and, likely, by climate change. Thus, aiming at assessing its vulnerability, this study includes a general characterization of climate variability in eight selected locations, both in northern and southern Bulgaria. Trend tests were applied to monthly precipitation, maximum and minimum temperature and to the Standardized Precipitation Index with two-month time step (SPI-2) relative to the period of 1951–2004. Negative trends were identified for precipitation and SPI-2 at various locations, mainly in the Thrace Plain, indicating that dryness is likely to be increasing in Bulgaria. The vulnerability of rainfed maize systems to drought was studied using the previously calibrated WinISAREG model and the Stewart’s yield model to compute both the relative yield decrease (RYD) due to water stress and the corresponding net irrigation required to overcome those losses. Results identified a strong relation between SPI-2 for July–August (SPI-2_July–Aug) and RYD. Results also show that yield losses are higher when the soils have a smaller soil water holding capacity. For the various regions under study, thresholds for RYD were defined considering the related economic impacts and the influence of soil characteristics on the vulnerability of the rainfed maize systems. Finally, to support drought risk management, SPI-2_July–Aug thresholds were developed to be used as indicators of the economic risk of rainfed maize for various climate regions and soil groups in Bulgaria.  相似文献   

Studying intensive convection in Perm krai using the WRF model     

N. A. Kalinin  A. L. Vetrov  E. M. Sviyazov  E. V. Popova 《Russian Meteorology and Hydrology》2013,38(9):598-604

Analyzed is a development of cloud convective system of short duration accompanied by severe thunderstorms, showers, squalls up to 22 m/s, and hail with the diameter reaching 20 mm and more in the afternoon on June 9, 2012 on the territory of Perm krai. An assessment of the convection development using the WRF-ARW model demonstrated that it simulates adequately the formation of convective systems on the territory of Perm krai. However, the zones of intensive precipitation coincide with its actual distribution not always. The Grell-Devenyi parameterization of convection gives the best results. The model does not simulate the hail formation processes: despite the fact of the development of this phenomenon on the territory of Perm krai on June 9, 2012, no hail formation was predicted by the model computations within the computational domain.  相似文献   

Astronomical and physical aspects of the Chelyabinsk event (February 15, 2013)     

V. V. Emel’yanenko  O. P. Popova  N. N. Chugai  M. A. Shelyakov  Yu. V. Pakhomov  B. M. Shustov  V. V. Shuvalov  E. E. Biryukov  Yu. S. Rybnov  M. Ya. Marov  L. V. Rykhlova  S. A. Naroenkov  A. P. Kartashova  V. A. Kharlamov  I. A. Trubetskaya 《Solar System Research》2013,47(4):240-254

Various observational data including infrasound, seismic, optical (onboard) monitoring, ground video and photo records, and evidence from witnesses of the Chelyabinsk event on February 15, 2013, have been analyzed. The extensive material gathered has provided a base for investigations of the physical properties of the object, the results of which are discussed. A bolide light curve is constructed, which shows a multiplicity of flashes. Estimations of the energy of the meteoroid explosion, which took place in the atmosphere at an altitude of about 23 km, show evidence of the formation of a high-power shock wave equivalent to 300–500 kilotons of TNT. The object diameter corresponding to this energy falls within the range 16–19 m. The trajectory of the meteor is outlined. It is preliminarily concluded that the Chelyabinsk meteorite was a representative the Apollo asteroid family.  相似文献   

Magnetic field dynamics based on SOHO/MDI data in the region of flares related to halo coronal mass ejections     

V. G. Fainshtein  T. E. Popova  L. K. Kashapova 《Geomagnetism and Aeronomy》2012,52(8):1075-1086

Variations in the photospheric magnetic field in the region of solar flares, related to halo coronal mass ejections (HCMEs) with velocities V > 1500, 1000 < V < 1500, and V < 650 km/s, have been studied based on SOHO/MDI data. Using data with a time resolution of 96 min, it has been indicated that on average the ??B _L?? and ??|B _L|?? field characteristics increase nonmonotonically during 1?C1.5 days before a flare and decrease during 0.5?C1 days after a flare for groups of ejections with V > 1000 km/s for all considered HCME groups. Angle brackets designate averaging of the measured B _L magnetic field component and its magnitude |B _L| within an area with specified dimensions and the center coincident with the projection onto the region where the flare center field is measured. It has been established that a solar flare related to an HCME originates when the ??B _L?? and ??|B _L|?? values are larger than the boundary values in the flare region. Based on 1-min data, it has been found for several HCMEs with V > 1500 km/s that the beginning of powerful flares related to ejections is accompanied by rapid impulsive or stepped variations in ??B _L?? and ??|B _L|?? near the center of a flare with a size of approximately 4.5°. It has been established that the HCME velocity positively correlates with the |??B _L??| value at the flare onset.  相似文献   

Generation of electromagnetic oscillations at frequencies of the lower hybrid and bounce resonance in mirror magnetic traps: Laboratory and rocket experiments     

A. S. Belov  G. A. Markov  L. L. Popova  Yu. V. Chugunov 《Geomagnetism and Aeronomy》2009,49(2):187-195

The generation of electromagnetic oscillations in the vicinity of the lower hybrid resonance and at the frequency of bounce oscillations of fast electrons in the plasma resonator of the magnetospheric type, formed by an HF discharge in a mirror magnetic trap, has been detected and studied. The results of the field rocket experiments aimed at stimulating maser effects, including such effects at frequencies of bounce oscillations of 40-keV electrons in the magnetospheric flux tube of the geomagnetic field, are discussed.  相似文献   

Method of composed distributions for assessing the maximal water discharges in the Amur river with the effect of runoff regulation taken into account     

M. V. Bolgov  N. O. Popova  M. K. Filimonova 《Water Resources》2016,43(3):448-458

The solution of the problem of evaluating the characteristics of maximal runoff by composed-distribution method is considered for the case of the confluence zone of the Zeya and Amur rivers. The method of solution of the probability problem is based on the construction of a random process of mean daily water discharges by simulating the inflow from unregulated river reaches and taking into account the reservoir-operating curve. The subsequent transformation of inflow in the channel system provides the values of runoff and their probability distribution in the required section.  相似文献   

Climatic Reasons for the Current Expansion of the Range of the Italian Locust in Russia and Neighboring Countries     

Popova  E. N.  Popov  I. O. 《Doklady Earth Sciences》2019,488(2):1256-1258

Doklady Earth Sciences - The species climatic range of a dangerous locust pest, called the Italian locust, was modelled for the territories of Russia and neighboring countries over two time periods...  相似文献   

Sarmatia-Volgo-Uralia junction zone: Isotopic-geochronologic characteristic of supracrustal rocks and granitoids     

E. V. Bibikova  S. V. Bogdanova  A. V. Postnikov  L. P. Popova  T. I. Kirnozova  M. M. Fugzan  V. V. Glushchenko 《Stratigraphy and Geological Correlation》2009,17(6):561-573

The geochronologic (U-Pb isotopic system of zircons) and isotopic-geochemical (Sm-Nd isotopic system of the bulk rock) studies were performed along the profile extending from the eastern Sarmatia (in the west) to the Middle Volga megablock of Volgo-Uralia (in the east), i.e., across the entire junction zone for dating the integration of Sarmatia and Volgo-Uralia, representing two segments of the East European Craton. It is established that the examined rocks are characterized by the Paleoproterozoic Nd isotopic model age, which varies from 2.1 and 2.4 Ga, except for some samples indicating a similar age of the crust through the entire Sarmatia-Volgo-Uralia junction zone. The highly metamorphosed complexes of the granulite and amphibolite facies constituting the southwestern margin of Volgo-Uralia are Paleoproterozoic, not Archean, in age, contrary to previous views. Two Early Paleoproterozoic lithotectonic complexes are defined in Volgo-Uralia: South Volga metasedimentary and Tersa metasedimentary-volcanogenic. The obtained data confirm the asynchronous integration of individual segments into the East European Craton: the integration of Sarmatia and Volgo-Uralia approximately 2100–2000 Ma ago was followed by the conjunction of this newly-formed continent with Fennoscandia ca. 1800 Ma ago.  相似文献   

Experimental study of fluorite solubility in acidic solutions as a method for boron fluoride complexes studying     

M. E. Tarnopolskaia  A. Yu. Bychkov  Yu. V. Shvarov  Yu. A. Popova 《Geochemistry International》2017,55(4):355-359

Fluorite solubility in HCl and HF solutions with varied concentrations of boric acid was studied at 81, 155, and 208°C and saturated vapor pressure. Our experimental results demonstrate that fluorite solubility increases with increasing B(OH)₃ concentration, and this was interpreted as the formation of the BF3OH–complex (Ryss, 1956). The experimental data were used to determine, using the OptimA software, the free energies of formation of HF°(aq) and, which were then used to calculate the constants of the reactions HF = H⁺ + F^– (1) and B(OH)₃(aq) + 2H⁺ + 3 F^– (2). The pK ₁ values are 3.71 ± 0.013, 4.28 ± 0.015, and 4.89 ± 0.017 and pK ₂ 13.60 ± 0.02, 13.99 ± 0.02, and 14.95 ± 0.03 at saturated vapor pressure and 81, 155, and 208°C, respectively.  相似文献   

On the correct use of cumulative applied climate indices for studying biological objects     

E. N. Popova  V. V. Yasyukevich  I. O. Popov 《Russian Meteorology and Hydrology》2017,42(10):661-664

The cumulative applied climate indices SAT and SET used in the Russian literature are considered in detail. These indices differ in calculation methods and, consequently, their values differ in different regions. The example is presented of the incorrect use of these indices by some authors for studying biological objects which leads to false conclusions. The method of calculation of the foreign applied climate index GDD is given. This index corresponds to the Russian index SET, and its interpretation as a counterpart of SAT is wrong.  相似文献