Mirseid Akperov
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Scopus Publications
Scopus Publications
Mirseid Akperov, Alexey V. Eliseev, Annette Rinke, Igor I. Mokhov, Vladimir A. Semenov, Mariya Dembitskaya, Heidrun Matthes, Muralidhar Adakudlu, Fredrik Boberg, Jens H. Christensen,et al.
Elsevier BV
M. G. Akperov and I. I. Mokhov
Pleiades Publishing Ltd
B. A. Babanov, V. A. Semenov, M. G. Akperov, I. I. Mokhov, and N. S. Keenlyside
Pleiades Publishing Ltd
M. G. Akperov and I. I. Mokhov
Pleiades Publishing Ltd
M. G. Akperov and A. V. Eliseev
Pleiades Publishing Ltd
Ralf Jaiser, M. Akperov, A. Timazhev, E. Romanowsky, D. Handorf, and I.I. Mokhov
Schweizerbart
M. G. Akperov, A. V. Eliseev, I. I. Mokhov, V. A. Semenov, M. R. Parfenova, and T. Koenigk
Allerton Press
Mirseid Akperov, Wenxin Zhang, Paul A Miller, Igor I Mokhov, Vladimir A Semenov, Heidrun Matthes, Benjamin Smith, and Annette Rinke
IOP Publishing
Abstract Arctic cyclones, as a prevalent feature in the coupled dynamics of the Arctic climate system, have large impacts on the atmospheric transport of heat and moisture and deformation and drifting of sea ice. Previous studies based on historical and future simulations with climate models suggest that Arctic cyclogenesis is affected by the Arctic amplification of global warming, for instance, a growing land-sea thermal contrast. We thus hypothesize that biogeophysical feedbacks (BF) over the land, here mainly referring to the albedo-induced warming in spring and evaporative cooling in summer, may have the potential to significantly change cyclone activity in the Arctic. Based on a regional Earth system model (RCA-GUESS) which couples a dynamic vegetation model and a regional atmospheric model and an algorithm of cyclone detection and tracking, this study assesses for the first time the impacts of BF on the characteristics of Arctic cyclones under three IPCC Representative Concentration Pathways scenarios (i.e. RCP2.6, RCP4.5 and RCP8.5). Our analysis focuses on the spring- and summer time periods, since previous studies showed BF are the most pronounced in these seasons. We find that BF induced by changes in surface heat fluxes lead to changes in land-sea thermal contrast and atmospheric stability. This, in turn, noticeably changes the atmospheric baroclinicity and, thus, leads to a change of cyclone activity in the Arctic, in particular to the increase of cyclone frequency over the Arctic Ocean in spring. This study highlights the importance of accounting for BF in the prediction of Arctic cyclones and the role of circulation in the Arctic regional Earth system.
M A Dembitskaya, M Akperov, V A Semenov, I I Mokhov, D D Bokuchava, W Dorn, and A Rinke
IOP Publishing
Abstract The impact of sea ice concentration (SIC) changes in the Nordic Seas on the winter cyclone activity in the Nordic Seas is analyzed in 10-member ensemble simulations with the coupled Arctic atmosphere-ocean-sea ice model HIRHAM-NAOSIM for the 1979–2016 period. The analysis reveals that anomalously low SIC in the Nordic Seas leads to decrease in vertical atmospheric static stability, and thus may result in favorable conditions for cyclogenesis in the Nordic Seas. Our analysis also shows a statistically significant increase of cyclone frequency over the Nordic Seas under conditions of the low SIC regime.
A I Narizhnaya, A V Chernokulsky, M G Akperov, D G Chechin, I Esau, and A V Timazhev
IOP Publishing
Abstract In this study, we evaluated the climatology and interannual variability of marine cold-air outbreaks (MCAOs) in the Russian Arctic marginal seas (from the Barents to Chukchi seas). We used a simple index for identifying MCAOs based on the vertical potential temperature gradient between the sea surface and the 800 hPa level. We calculated the index using 6-hourly Era-Interim data for the 1979–2018 period. Given the index, we evaluated spatial and temporal variability of weak, medium, and strong MCAOs frequency as well as their dependence on sea-ice concentration using non-parametric tests. The most intense MCAOs were found in the Barents and Kara seas. The annual cycle maximum for the western Russian Arctic (WRA) were found in wintertime, while it was revealed in mid-late autumn for the eastern Russian Arctic (ERA). In the WRA, we found a statistically significant decrease in amount of strong MCAOs in winter and late autumn and a general strengthening of MCAOs in spring. Meanwhile, over the ERA region, increase of moderate and weak cold-air intrusions during October and November was revealed.
Mirseid Akperov, Vladimir A Semenov, Igor I Mokhov, Wolfgang Dorn, and Annette Rinke
IOP Publishing
Abstract The impact of the Atlantic water inflow (AW inflow) into the Barents Sea on the regional cyclone activity in winter is analyzed in 10 ensemble simulations with the coupled Arctic atmosphere-ocean-sea ice model HIRHAM-NAOSIM for the 1979–2016 period. The model shows a statistically robust connection between AW inflow and climate variability in the Barents Sea. The analysis reveals that anomalously high AW inflow leads to changes in static stability and wind shear in the lower troposphere, and thus favorable conditions for cyclogenesis in the Barents/Kara Seas. The frequency of occurrence of cyclones, but particularly of intense cyclones, is increased over the Barents Sea. Furthermore, the cyclones in the Barents Sea become larger (increased radius) and stronger (increased intensity) in response to an increased AW inflow into the Barents Sea, compared to years of anomalously low AW inflow.
Mirseid Akperov, Annette Rinke, Igor I. Mokhov, Vladimir A. Semenov, Mariya R. Parfenova, Heidrun Matthes, Muralidhar Adakudlu, Fredrik Boberg, Jens H. Christensen, Mariya A. Dembitskaya,et al.
Elsevier BV
M Akperov, A Rinke, I I Mokhov, H Matthes, V A Semenov, M Adakudlu, J Cassano, J H Christensen, M A Dembitskaya, K Dethloff,et al.
IOP Publishing
The ability of state-of-the-art regional climate models (RCMs) to simulate the trends of intense cyclone activity in the Arctic is assessed based on an ensemble of 13 simulations from 11 models from the Arctic-CORDEX initiative. Some models employ large-scale spectral nudging techniques. Cyclone characteristics simulated by the ensemble in winter and summer are compared with the results from four reanalyses (ERA-Interim, NCEP-CFSR, NASA-MERRA2 and JMA-JRA55) in winter and summer for 1981-2010 period.
M. G. Akperov, I. I. Mokhov, M. A. Dembitskaya, M. R. Parfenova, and A. Rinke
Allerton Press
M. G. Akperov, V. A. Semenov, I. I. Mokhov, M. A. Dembitskaya, D. D. Bokuchava, A. Rinke, and W. Dorn
The Russian Academy of Sciences
The influence of the oceanic heat inflow into the Barents Sea on the sea ice concentration and atmospheric characteristics, including the atmospheric static stability during winter months, is investigated on the basis of the results of ensemble simulations with the regional climate model HIRHAM/NAOSIM for the Arctic. The static stability of the atmosphere is the important indicator of the spatial and temporal variability of polar mesocyclones in the Arctic region. The results of the HIRHAM/NAOSIM regional climate model ensemble simulations (RCM) for the period from 1979 to 2016 were used for the analysis. The initial and lateral boundary conditions for RCM in the atmosphere were set in accordance with the ERA-Interim reanalysis data. An analysis of 10 ensemble simulations with identical boundary conditions and the same radiation forcing for the Arctic was performed. Various realizations of ensemble simulations with RCM were obtained by changing the initial conditions for integrating the oceanic block of the model. Different realizations of ensemble simulations with RCM are obtained by changing the initial conditions of the model oceanic block integration. The composites method was used for the analysis, i.e. the difference between the mean values for years with the maximum and minimum inflow of oceanic water into the Barents Sea. The statistical significance of the results (at a significance level of p < 0.05) was estimated using Student's t-test. In general, the regional climate model reproduces the seasonal changes in the inflow of the oceanic water and heat into the Barents Sea reasonably well. There is a strong relationship between the changes in the oceanic water and ocean heat inflow, sea ice concentration, and surface air temperature in the Barents Sea. Herewith, the increase in the oceanic water inflow into the Barents Sea in winter leads to a decrease in static stability, which contributes to changes in regional cyclonic activity. The decrease of the static stability is most pronounced in the southern part of the Barents Sea and also to the west of Svalbard.
Sergey Denisov, Mirseid Akperov, Maxim Arzhanov, Vladimir Semenov, Alexander Timazhev, Kirill Muryshev, and Igor Mokhov
SPIE
Current estimates of methane emissions from high-latitude wetland ecosystems have significant inter-model variation, one of the reasons for which may be the internal variability of atmospheric circulation. This paper analyzes the effects of internal atmospheric variability on variations in methane emissions from Western Siberia. For average annual emission values, the uncertainty rate associated with climatic noise was 10%, and for individual months, 7–35%.
Mirseid Akperov, Igor Mokhov, Dembitskaya Mariya, and Parfenova Mariya
SPIE
Based on the NCEP / NCAR reanalysis data, the characteristics of seasonal variations in cyclonic and anticyclonic activity over the Baikal Basin in 1980–2016 were analyzed. The estimates for the latitudinal dependence of cyclonic and anticyclonic activity in the atmosphere for the longitude belt 98 °E — 112 °E (corresponding to the longitudinal extent of the Baikal Basin) are obtained. Comparison of the two periods - the end of the 20th century (from 1980 till 1994 — period I) and the beginning of the 21st century (from 2002 till 2016 — period II) - revealed a decrease in cyclonic and an increase in anticyclonic activity over the Baikal Basin in summer. At the same time, the intensification of winter cyclonic activity in middle latitudes and anticyclonic activity in higher latitudes was noted.
Fedor Kozlov, Alexander Chernokulsky, Mirseid Akperov, Vyacheslav Khon, Igor I. Mokhov, Alexander Osipov, Vladimir A. Semenov, and Alexander Timazhev
SPIE
The contribution of dynamic and thermodynamic causes in changes of precipitation character in Northern Eurasia that is expressed in increase of convective and decrease of large-scale precipitation, is still undetermined. Here, we estimate influence of atmospheric circulation on various characteristics of convective and large-scale precipitation in Northern Eurasia using correlation and regression analyses. We estimate different measures for atmospheric circulation including frequency of cyclones and anticyclones, blocking duration, intensity of the main atmospheric centers of action. Correlation and regression analyses were carried out using nonparametric Mann-Kendall correlation and Theil-Sen estimator. We revealed local response of precipitation on circulation characteristics, which strength varies in space and time. For some regions and seasons, opposite responses for convective and large-scale precipitation were found. Therefore, changing character of precipitation over Northern Eurasia can partly be explained by dynamical factors. Nevertheless, the main reason for increase of convective and decrease of large-scale precipitation is presumably associated with thermodynamics factors, namely increase of surface air temperature and humidity that resulting in convective instability growth.
Matthias Zahn, Mirseid Akperov, Annette Rinke, Frauke Feser, and Igor I. Mokhov
American Geophysical Union (AGU)
Cyclones in the Arctic are detected and tracked in four different reanalysis data sets from 1981 to 2010. In great detail the spatial and seasonal patterns of changes are scrutinized with regards to their frequencies, depths, and sizes. We find common spatial patterns for their occurrences, with centers of main activity over the seas in winter, and more activity over land and over the North Pole in summer. The deep cyclones are more frequent in winter, and the number of weak cyclones peaks in summer. Overall, we find a good agreement of our tracking results across the different reanalyses. Regarding the frequency changes, we find strong decreases in the Barents Sea and along the Russian coast toward the North Pole and increases over most of the central Arctic Ocean and toward the Pacific in winter. Areas of increasing and decreasing frequencies are of similar size in winter. In summer there is a longish region of increase from the Laptev Sea toward Greenland, over the Canadian archipelago, and over some smaller regions west of Novaya Zemlya and over the Russia. The larger part of the Arctic experiences a frequency decrease. All the summer changes are found statistically unrelated to the winter patterns. In addition, the frequency changes are found unrelated to changes in cyclone depth and size. There is generally good agreement across the different reanalyses in the spatial patterns of the trend sign. However, the magnitudes of changes in a particular region may strongly differ across the data.
Mirseid Akperov, Annette Rinke, Igor I. Mokhov, Heidrun Matthes, Vladimir A. Semenov, Muralidhar Adakudlu, John Cassano, Jens H. Christensen, Mariya A. Dembitskaya, Klaus Dethloff,et al.
American Geophysical Union (AGU)
The ability of state‐of‐the‐art regional climate models to simulate cyclone activity in the Arctic is assessed based on an ensemble of 13 simulations from 11 models from the Arctic‐CORDEX initiative. Some models employ large‐scale spectral nudging techniques. Cyclone characteristics simulated by the ensemble are compared with the results forced by four reanalyses (ERA‐Interim, National Centers for Environmental Prediction‐Climate Forecast System Reanalysis, National Aeronautics and Space Administration‐Modern‐Era Retrospective analysis for Research and Applications Version 2, and Japan Meteorological Agency‐Japanese 55‐year reanalysis) in winter and summer for 1981–2010 period. In addition, we compare cyclone statistics between ERA‐Interim and the Arctic System Reanalysis reanalyses for 2000–2010. Biases in cyclone frequency, intensity, and size over the Arctic are also quantified. Variations in cyclone frequency across the models are partly attributed to the differences in cyclone frequency over land. The variations across the models are largest for small and shallow cyclones for both seasons. A connection between biases in the zonal wind at 200 hPa and cyclone characteristics is found for both seasons. Most models underestimate zonal wind speed in both seasons, which likely leads to underestimation of cyclone mean depth and deep cyclone frequency in the Arctic. In general, the regional climate models are able to represent the spatial distribution of cyclone characteristics in the Arctic but models that employ large‐scale spectral nudging show a better agreement with ERA‐Interim reanalysis than the rest of the models. Trends also exhibit the benefits of nudging. Models with spectral nudging are able to reproduce the cyclone trends, whereas most of the nonnudged models fail to do so. However, the cyclone characteristics and trends are sensitive to the choice of nudged variables.
Andrew Jensen, Mirseid Akperov, Igor Mokhov, Anthony Lupo, and Fengpeng Sun
MDPI AG
The dynamic character of an enstrophy-based diagnostic, previously used in the study of atmospheric blocking, is examined here, in near-term future simulations from the Institut Pierre Simon Laplace Climate Model version 4 (IPSL-CM4) and version 5 (IPSL-CM5) climate models of the Northern Hemisphere flow for moderate climate change scenarios. Previous research has shown that integrated regional enstrophy (IE) increases during blocking onset and decay, which is a reflection of planetary-scale instability. In addition, IE has been shown previously to increase during flow regime transitions in general, even those not associated with blocking events. Here, a 31-year IE diagnostic time series is examined for changes in short term (5–40 days) planetary-scale variability that may correspond flow regime changes in an increased carbon dioxide environment. The time-series analysis herein indicates that the IE diagnostic provides evidence for approximately 30–35 atmospheric flow regime transitions per year in a warmer climate, which is similar to that of the control run and the latest 30-year observed climate, as derived from re-analyses. This result has implications regarding the predictability of weather in a warmer world.
Mirseid Akperov, Igor I. Mokhov, Mariya A. Dembitskaya, and Mariya R. Parfenova
SPIE
Estimates of the tropospheric lapse rate γ and an analysis of its connection with the surface air temperature Ts in high latitudes of the Northern Hemisphere for summer and winter are performed using monthly-mean data from the ERAInterim reanalysis (1979-2014). According to the reanalysis data the lapse rate values increase from 4.7 K/km near the pole to 5.3 K/km in subpolar latitudes in winter and from 5.3 to 6.1 K/km in summer. The estimates of dγ/dTs in interannual variability are found positive over the most part of the Arctic from reanalysis data. At the same time, a negative correlation between γ and Ts was found for the Atlantic sector of the Arctic in winter and for the central Arctic in summer. It is also noted regional peculiarities in the connection of lapse rate with Arctic oscillation for winter and summer.
Alexander Chernokulsky, Mirseid Akperov, Natalia Podnebesnykh, and Igor I. Mokhov
SPIE
A comprehensive intercomparison of midlatitude storm characteristics is presented. Extratropical storm characteristics were derived from 16 reanalysis-based objective automated algorithms for cyclone identification and tracking from the IMILAST project and from manual method based on an expert inspection of weather charts. The analysis was carried out for the Siberian region (50–80N, 60–110E) for two seasons (winter of 2007/08 and summer of 2008). Most of the automated algorithms show 1.5–3 times more cyclones and 3–5 times more cyclone tracks in the Siberian region compare to the manual method. The algorithms show a good agreement with the manual method for spatial distribution of cyclones and tracks number with spatial correlation coefficient varies around 0.8–0.9 in summer and around 0.7–0.9 in winter for most of the algorithms. Two ranking measures were used to evaluate similarity of objective algorithms with the manual method.
Andrew Jensen, Anthony Lupo, Igor Mokhov, Mirseid Akperov, and DeVondria Reynolds
MDPI AG
Enstrophy in a fluid relates to the dissipation tendency in a fluid that has use in studying turbulent flows. It also corresponds to vorticity as kinetic energy does to velocity. Earlier work showed that the integrated regional enstrophy (IRE) was related to the sum of the positive Lyapunov exponents. Lyapunov exponents are the characteristic exponent(s) of a dynamic system or a measure of the divergence or convergence of system trajectories that are initially close together. Relatively high values of IRE derived from an atmospheric flow field in the study of atmospheric blocking was identified with the onset or demise of blocking events, but also transitions of the large-scale flow in general. Kolmogorv–Sinai Entropy (KSE), also known as metric entropy, is related to the sum of the positive Lyapunov exponents as well. This quantity can be thought of as a measure of predictability (higher values, less predictability) and will be non-zero for a chaotic system. Thus, the measure of IRE is related to KSE as well. This study will show that relatively low (high) values of IRE derived from atmospheric flows correspond to a more stable (transitioning) large-scale flow with a greater (lesser) degree of predictability and KSE. The transition is least predictable and should be associated with higher IRE and KSE.
Мирсеид Акперов
Akademizdatcenter Nauka