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1.
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2.
The results of 2-year (2010–2012) measurements of the concentrations of organic carbon (OC) and elemental carbon (EC), which were taken at the Zotino Tall Tower Observatory (ZOTTO) Siberian background station (61° N, 89° E), are given. Despite the fact that this station is located far from populated areas and industrial zones, the concentrations of OC and EC in the atmosphere over boreal forests in central Siberia significantly exceed their background values. In winter and fall, high concentrations of atmospheric carbonaceous aerosol particles are caused by the long-range transport (~1000 km) of air masses that accumulate pollutants from large cities located in both southern and southwestern regions of Siberia. In spring and summer, the pollution level is also high due to regional forest fires and agricultural burning in the steppe zone of western Siberia in the Russian–Kazakh border region. Background concentrations of carbonaceous aerosol particles were observed within relatively short time intervals whose total duration was no more than 20% of the entire observation period. In summer, variations in the background concentrations of OC closely correlated with air temperature, which implies that the biogenic sources of organic-particle formation are dominating.  相似文献   

3.
We describe the specific features of the summer 2010 emergency conditions in the European part of the Russian Federation, when an anomalous heat wave (the monthly mean temperatures in the summer months were 5–9°C higher than those for 2002–2009) and prolonged blocking anticyclones led to large wildfires. We analyze their causes and consequences. The features of the satellite system for operational fire monitoring (constructed at the Aerospace Scientific Center) and examples of its application in summer 2010 are presented. On the basis of the results of processing of satellite images of low (250–1000 m), medium (∼30–50 m), and high (∼6 m) resolutions, we found that the total area covered by fire from March to November of 2010 amounted to approximately 10.9 million hectares for the entire territory of the country and and 2.2 million hectares for its European part. Daily histograms of areas covered by fire in the summer months of 2010 were constructed. On the basis of these data and empirical models, we estimate the daily emissions of carbon monoxide (CO) from wildfires in the summer months of 2010 for the European part of Russia and Moscow oblast. On some days in August 2010, these emissions reached 15000–27000 t for the European part of Russia and 3000–7500 t for Moscow oblast. On the basis of analysis of data from the AIRS spectrometer (Aqua satellite), we derived the spatial distribution of CO concentrations at heights of 2 to 10 km above the territory of the Eastern and Central Europe. Moscow was shown to have been most severely affected by smoke from wildfires occurring on August 6–9, 2010, when the concentrations of harmful gases (CO2, CO, CH4, and O3) and aerosols in the air significantly exceeded both the daily and the one-hour maximum allowable concentrations.  相似文献   

4.
The spatial structure of surface air temperature (SAT) anomalies in the extratropical latitudes of the Northern Hemisphere (NH) during the 20th century is studied from the data obtained over the period 1892–1999. The expansion of the mean (over the winter and summer periods) SAT anomalies into empirical orthogonal functions (EOFs) is used for analysis. It is shown that variations in the mean air temperature in the Arctic region (within the latitudes 60°–90°N) during both the winter and summer periods can be described with a high accuracy by two spatial orthogonal modes of variability. For the winter period, these are the EOF related to the leading mode of variability of large-scale atmospheric circulation in the NH, the North Atlantic Oscillation, and the spatially localized (in the Arctic) EOF, which describes the Arctic warming of the mid-20th century. The expansion coefficient of this EOF does not correlate with the indices of atmospheric circulation and is hypothetically related to variations in the area of the Arctic ice cover that are due to long-period variations in the influx of oceanic heat from the Atlantic. On the whole, a significantly weaker relation to the atmospheric circulation is characteristic of the summer period. The first leading variability mode describes a positive temperature trend of the past decades, which is hypothetically related to global warming, while the second leading EOF describes a long-period oscillation. On the whole, the results of analysis suggest a significant effect of natural climatic variability on air-temperature anomalies in the NH high latitudes and possible difficulties in isolating an anthropogenic component of climate changes.  相似文献   

5.
The evolution of smoke plume over European Russia (ER) during the massive forest and peatbog fires of summer 2010 has been studied using observations of aerosol optical depth (AOD) from MODIS instruments (both Aqua and Terra platforms), objective analysis of meteorological fields performed at the Russian Hydrometeorological Research Center, NCEP/NCAR reanalysis, as well as upper air data. A relation between the structure inhomogeneities of the AOD field and regional atmospheric circulation has been found. It is shown that, on August 5–9, 2010, the maximum of smoke pollution did complete turn around Moscow, while remaining at a distance of 200 to 650 km from the megacity. Both regionally averaged shortwave aerosol radiative forcings (ARFs) at the top and the bottom of the atmosphere are estimated for the period of extreme smoke pollution over ER. The spatial distributions of ARF values over the territory of the region and the estimates of the local and spatially distributed thermal effects of smoke aerosol are given. It is shown that, on August 5–9, 2010, the spatial distribution of AOD and the calculated thermal effects of smoke aerosol were in agreement with the spatial distributions of air-temperature anomalies observed in the lower 1.5-km layer of the atmosphere. MODIS’s AOD data obtained during the wildfires were validated by AOD observations from the CIMEL sun photometer operated at the AERONET station Zvenigorod.  相似文献   

6.
The results of meteorological ground-based observations in Moscow (mainly at Moscow State University (MSU)) in summer 2010 are discussed. It is shown that the anomalous heat of 2010 has no analogs in the history of meteorological observations in the Russian capital in either the record-breaking values themselves or in their duration. Both the secular records of the monthly mean air temperatures in July and August over the past 230 years and the absolute temperature maximum over the past 130 years were exceeded. For the first time in the history of regular meteorological measurements, the maximal air temperature in Moscow exceeded +38°C, the diurnal mean temperature exceeded +30°C, the monthly mean temperature exceeded +26°C, the soil surface temperature exceeded +60°C, and the deficit of water vapor saturation exceeded 50 hPa. On the whole, the tropical air, which dominated in Moscow, was to a larger degree anomalously hot than anomalously dry. The least relative humidity during the catastrophic heat (16%) only approached the historical minimum (15%). For the first time in the history of measurements for July, the amount of precipitation in July 2010 was only 7.4 mm. In total, these conditions were responsible for the appearance of mass ignition centers in the Moscow region and, as a consequence, of dense smog. The record-breaking ground temperatures over the past 45 years associated with the catastrophic heat were observed at a depth of 320 cm up to the end of 2010.  相似文献   

7.
东海营养盐结构的时空分布及其对浮游植物的限制   总被引：2，自引：0，他引：2  
本文根据2013年东海海域(120°—128°E、25°—33°N)春、夏、秋、冬的4个航次调查资料,分析了营养盐结构的时空分布并探讨其对浮游植物生长限制的情况。结果表明:(1)东海DIN(无机氮)/P(磷)、Si(硅)/DIN及Si/P比值受各种水团及浮游植物生长周期的影响较为明显,长江冲淡水与沿岸水的交汇作用控制着全航次DIN/P比值,基本呈近岸高、远海低的分布规律,而Si/DIN比值的分布则相反。春、夏季Si/P高值区主要分布在近岸,而秋、冬季则开始由中部海域向远海扩展。(2)研究海域浮游植物的生长主要受到N和P的限制,126°E以西的近岸及中部海域以P限制为主,而126°E以东的黑潮区受N限制;在季节变化上又以夏季受到营养盐的限制最明显。(3)与2001—2010年同期历史资料相比,2013年夏季航次受P限制站位数量比过往10年有所增加,限制范围由28°—32°N、123°E以西的长江口及浙北沿岸海域扩展到了126°E以西的东海中部及近岸水域;受N限制站位基本集中在126°—127°E以东黑潮区海域,但空间范围比十年前增大。  相似文献   

8.
Modern climatic changes for 1991–2013 in the lower 4-km layer of the atmosphere in the Moscow region are discussed based on long-term measurements using radiosondes in Dolgoprudny near Moscow and sensors installed on a high mast in Obninsk and on a television tower in Ostankino in Moscow. It is shown that at the end of the 20th century and the beginning of the 21st century the mean-annual air temperature at all heights from 2 to 4000 m increased by an average of 0.1°C per year. In recent years, the warming has slowed. Over the last two decades, long-term changes were multidirectional, depending on the season: warming in May–December, cooling in January–February, and no statistically significant changes in March and April. The probable reason for the temperature decrease in the middle of the cold period is changes in the large-scale atmospheric circulation during recent years (the negative phase of the North Atlantic Oscillation in early 2010s). In recent years, the Moscow region climate continentality has increased because of warming in summer and cooling in winter, despite the secular decreasing trend, which was noted before. Mean daily and annual warming rates in Dolgoprudny were higher than in Obninsk. The probable reason is the northward construction expansion and the strengthening of the Moscow heat island. The highest annual temperature amplitude is recorded at heights of 200–300 m.  相似文献   

9.
Giant jellyfish (Nemopilema nomurai) outbreaks in relation to satellite sea surface temperature (SST) and chlorophyll-a concentrations (Chl-a) were investigated in the Yellow Sea and East China Sea (YECS) from 1998 to 2010. Temperature, eutrophication, and match–mismatch hypotheses were examined to explain long-term increases and recent reductions of N. nomurai outbreaks. We focused on the timing of SST reaching 15 °C, a critical temperature enabling polyps to induce strobilation and enabling released ephyra to grow. We analyzed the relationship of the timing with interannual variability of SST, Chl-a, and the timing of phytoplankton blooms. Different environmental characteristics among pre-jellyfish years (1998–2001), jellyfish years (2002–2007, 2009), and non-jellyfish years (2008, 2010) were assessed on this basis. The SST during late spring and early summer increased significantly from 1985 to 2007. This indicated that high SST is beneficial to the long-term increases in jellyfish outbreaks. SST was significantly lower in non-jellyfish years than in jellyfish years, suggesting that low SST might reduce the proliferation of N. nomurai. We identified three (winter, spring, and summer) major phytoplankton bloom regions and one summer decline region. Both Chl-a during non-blooming periods and the peak increased significantly from 1998 to 2010 in most of the YECS. This result indicates that eutrophication is beneficial to the long-term increases in jellyfish outbreaks. Timing of phytoplankton blooms varied interannually and spatially, and their match and mismatch to the timing of SST reaching 15 °C did not correspond to long-term increases in N. nomurai outbreaks and the recent absence.  相似文献   

10.
Time-series sediment traps were deployed during 1997–2000 in the northwestern North Pacific. The samples from 3000 m depth were investigated in order to study the silicoflagellate skeleton fluxes, the relationships with the geographical differences of their distribution, and their responses to temporal climate variations. At Station 50N (50°N, 165°E), located near the center of the Western Subarctic Gyre (WSG), subarctic-water taxa Distephanus speculum and Distephanus boliviensis dominated in the sinking assemblage. At Station KNOT (44°N, 155°E), located in the southwestern edge of the WSG, D. speculum also dominated throughout the sampled period. The warm-water taxon Dictyocha mandrai increased from the second half of 1998 to the first half of 1999, and the subtropical-water taxon Dictyocha messanensis also increased after the maximum period of D. mandrai flux. Not an obviously discernible seasonality was observed in the assemblages at Stations 50N and KNOT. At Station 40N (40°N, 165°E), at the south of the Subarctic Boundary, both the subarctic-water and the subtropical-water taxa dominated in winter and spring, and in summer and fall, respectively. The temporal assemblage variations at Station 40N significantly reflected the change of Sea Surface Temperature (SST) anomaly. This assemblage variation also implies which water mass, subarctic or subtropical, had more influence at Station 40N. The temporal successions of silicoflagellate assemblages at Station 40N are most likely due to the temporal oceanographic variability caused by global atmospheric changes. The differences of the seasonal flux pattern and the biogeochemical contribution of silicoflagellates at each station were due to the differences of ecosystem at each station.  相似文献   

11.
The surface area and volume densities (S and V) of the particles of stratospheric background aerosol in the 15–20 km and 20–25 km layers for 2002–2005 were obtained from measurements of the aerosol extinction coefficient with the SAGE III instrument by using the linear-regression method of solving the inverse problem. The measurements were taken within the latitudinal belts 43°–80°N and 34°–58°S. The spatial and temporal dependences of S and V demonstrate homogeneous distribution fields in summer, whereas noticeable inhomogeneities are observed in winter and early spring. In all years of the measurements, an increase in the integral characteristics of stratospheric background aerosol was observed during the fall-to-winter transition period. Longitudinal variations in S and V can be both slight and significant (50–70%). Analysis of the interannual variability of the mean areas and volumes of aerosol particles shows that their minima (as a rule) were observed in 2002 and their maxima were observed in 2005. In most of the cases, no monotonic annual variations in the aerosol characteristics are noted. The dependence of the aerosol parameters on the phase of the quasi-biennial oscillations of zonal wind in the stratosphere is observed. The data obtained for 2002–2005 are, on the whole, in good agreement with the climatological data obtained for 1996–1999.  相似文献   

12.
The air exchange between the Arctic and midlatitude regions is one of the processes forming the climate of the whole Northern Hemisphere. Analysis of the wind regime in the vicinity of the Arctic border (70° N) at the boundary between the 20th and 21st (1997–2004) centuries showed significant changes in the conditions of a meridional air transport between the Arctic and midlatitude regions as compared to the previous years (1960–1990). In this study, the wind fluxes of mass and heat (internal) and kinetic energies are estimated without consideration for turbulent and convective processes. The importance of spatial, seasonal, and interannual variations in wind velocity and air temperature in the formation of these fluxes is analyzed. It is shown that, during the period 1997–2004, an advective transport of energy from the northern latitudes occurred in the lower 6-km tropospheric layer at 70° N latitude over almost a whole year. Only in spring (April) did the wind fluxes bring heat energy from the south. The total amount of both heat and kinetic energies transported from the Arctic region in this way during a year is comparable to the mean amount of these energies contained in the whole atmosphere over the area bounded by 70° N latitude. The current spatial and temporal distributions of wind velocity and meridional mass and energy fluxes, which are presented in this study, may serve as additional information for interpreting data obtained from different on-site measurements in Arctic regions.  相似文献   

13.
Latitudinal position and wind speed of the Southern Hemisphere subtropical jet stream have been investigated on the basis of ERA-Interim, JRA-55, and NCEP–NCAR reanalysis data for 1948–2013. The analysis covers different time intervals in summer and winter seasons, as well as different spatial domains. It has been shown that the variability of the southern jet stream parameters in both winter and summer seasons is predominantly characterized by wind-speed weakening on the jet-stream axis and its poleward shift. The winter seasons of 2000–2013 identified a shift in the jet-stream axis toward the equator in the Atlantic (60°–0° W) and African (0°–60° E) sectors; the wind-speed increase in the Atlantic sector was statistically significant. The wind speed on the jet-stream axis in both winter and summer is closely related to the temperature difference in the upper tropospheric layer of 200–400 hPa between the latitudinal zones of 0°–30° S and 30°–60° S. A significant negative correlation (r = ?0.78) between wind speed and temperature difference has been revealed for the winter season in the upper tropospheric layer between the latitudinal zones of 30°–60° S and 60°–90° S, which can be explained by the Southern Annular Mode variability in this season. No such relationship has been found for the summer season.  相似文献   

14.
The fugacity of CO2 (fCO2) was measured underway from 27 May to 5 July 2006 in the Gulf of Guinea when the upwelling conditions were taking place. The equatorial and the coastal upwellings are responsible for the large CO2 outgassing observed in the tropical Atlantic. The highest fCO2 (655 μatm) was measured in the eastern coastal upwelling. However, area of low fCO2 are also observed. Those occurred north of 2°N, in the Guinea Current, and near 6°S close to the coast due to the Congo River discharge. The decrease of salinity is a major factor explaining low fCO2. In the South Equatorial Counter Current region, south of 6°S near 10°W, low fCO2 are not related to a salinity effect as this region is subject to excess evaporation. A comparison with the meridional transects of the RMS St Helena made in 1995–1996 near 15°W suggests that these low fCO2 or even slight undersaturations can be observed from about 4°S to 10°S. It seems that they occur mainly in boreal summer. They could be caused by transport of water that has been in contact with the atmosphere long enough to come close to equilibrium. The low fCO2 area are not reproduced by the CO2 climatology probably because of the coarse resolution and the lack of data in this region. Despite the low fCO2 area observed in 2006, the ΔfCO2 in 2006 is higher than the 1995 climatology for the region 10°S–2°N, 10°W–10°E suggesting that fCO2 is increasing over time but from the few cruises available, it is difficult to definitely conclude.  相似文献   

15.
The Mindanao Dome (MD) features prominent oceanic variability and is located geographically close to the bifurcation latitude Y b of the Pacific North Equatorial Current. In this study, the role of the MD in the variability of Y b is examined with 20 years of satellite altimetric sea surface height (SSH) data and a 1.5-layer linear Rossby wave model. It is shown that the seasonal variations of surface Y b are related to not only the SSH fluctuations near the bifurcation point (bifurcation box; 125°–130°E, 12°–15°N) but also those outstanding in the MD region (MD box; 127°–132°E, 6°–9°N). The impact of the MD SSH changes is significant when the bifurcation point stays at southerly latitudes during February–September, which hinders (delays) the southward leap (northward retreat) of Y b in April–May (July–August) and thus leads to the asymmetry of the mean Y b seasonal cycle (with a positive skewness of γ = +0.64). Such asymmetry also shows year-to-year variations depending on yearly mean Y b value. A southerly yearly mean Y b involves larger contribution of the MD and thus causes larger asymmetry of Y b seasonal cycle. At interannual and longer timescales, the MD acts to amplify the fluctuations of the bifurcation. It is responsible for about 20 % of the total low-frequency Y b variances and plays an important role in the 0.12° year?1 southward trend of Y b in the past two decades. The impact of the MD on Y b changes is becoming increasingly significant at various timescales such as the bifurcation point migrating southward in recent years.  相似文献   

16.
Cell densities of phycoerythrin-fluorescing cyanobacteria and other chlorophyll-fluorescing picophytoplankton in the 0.2–2.0 µm size fraction were investigated, using an epifluorescence microscope, in the western North Pacific Ocean (36.5–44.0 °N, 155.0°E) in the summer of 1989. Cyanobacteria were most abundant in the surface of the subtropical water (36.5–38.0°N) and less in the northern sea area (39.5–44.0°N). The cell density of other picophytoplankton was, however, high in the northern part and low in the subtropical water. Results showed that algae other than cyanobacteria may significantly contribute to the picophytoplankton community under the low water temperature conditions of open waters. Chlorophylla concentration represented well the abundance of picophytoplankton other than cyanobacteria, but had no significant correlation with the cyanobacteria cell density. Chlorophylla-based data must be interpreted with caution, since the abundances of cyanobacteria were often considerably different even though the chlorophylla concentrations were the same level.  相似文献   

17.
In the summer of 2010, the Moscow megacity during two months was within the zone of action of a blocking anticyclone. The accumulation of pollutants in a closed air mass sharply changed the surface air quality. At the end of July-the first half of August, the extreme situation became even more complicated, because the air from regions of turf and grass fires came into Moscow. According to measurement data of the Moscow IAP RAS station, the maximal hourly mean concentrations of chemically active gases NO, NO2, CO, O3, and SO2 were 175.9, 217.4, 15.8, 134.2, and 15.2 ppb, respectively. For NO2 and CO, these values are largest over the entire decadal period of observations at the station and many times exceed the MPC level (see table). The concentrations of greenhouse gases CO2, CH4, and nonmethane hydrocarbons also sharply increased. Analysis of the variability of gas contents in the surface air and in the atmospheric boundary layer showed a close relation between extreme changes in the atmospheric composition and its vertical stratification.  相似文献   

18.
南黄海浮游动物主要种类数量分布年间比较   总被引：3，自引：0，他引：3  
陈峻峰  左涛  王秀霞 《海洋学报》2013,35(6):195-203
分析对比1959年、1982年、1998-2000年以及2007-2010年4个不同时期南黄海中部（34.25°~37.45°N,122.00°~124.00°E）浮游动物主要优势种中华哲水蚤（Calanus sinicus）、太平洋磷虾（Euphausia pacifica）和强壮箭虫（Sagitta crassa）数量时空变化及其与温度、盐度和太平洋年代际震荡指数（Pacific Decadal Oscillation,PDO）变动的关系。结果显示,温度可能对中华哲水蚤和太平洋磷虾数量分布影响较大;强壮箭虫则受盐度影响较大。PDO暖位相时期中华哲水蚤和太平洋磷虾数量显著低于冷位相时期,强壮箭虫则相反。中华哲水蚤和太平洋磷虾丰度与提前3个月PDO值呈显著正相关,强壮箭虫丰度仅与当月PDO值呈显著正相关。  相似文献   

19.
A long-term mean turbulent mixing in the depth range of 200–1000 m produced by breaking of internal waves across the middle and low latitudes (40°S–40°N) of the Pacific between 160°W and 140°W is examined by applying fine-scale parameterization depending on strain variance to 8-year (2005–2012) Argo float data. Results show that elevated turbulent dissipation rate (ε) is related to significant topographic regions, along the equator, and on the northern side of 20°N spanning to 24°N throughout the depth range. Two patterns of latitudinal variations of ε and the corresponding diffusivity (Kρ) for different depth ranges are confirmed: One is for 200–450 m with significant larger ε and Kρ, and the maximum values are obtained between 4°N and 6°N, where eddy kinetic energy also reaches its maximum; The other is for 350–1000 m with smaller ε and Kρ, and the maximum values are obtained near the equator, and between 18°S and 12°S in the southern hemisphere, 20°N and 22°N in the northern hemisphere. Most elevated turbulent dissipation in the depth range of 350–1000 m relates to rough bottom roughness (correlation coefficient?=?0.63), excluding the equatorial area. In the temporal mean field, energy flux from surface wind stress to inertial motions is not significant enough to account for the relatively intensified turbulent mixing in the upper layer.  相似文献   

20.
The shortwave radiative forcings of smoke aerosol in the cloudless atmosphere during the summer fires of 2010 in European Russia were quantitatively estimated for the land surface and the atmospheric upper boundary from measurement data obtained at the Zvenigorod Scientific Station of the Obukhov Institute of Atmospheric Physics (OIAP ZSS), Russian Academy of Sciences. Variations in the temperature of the surface air layer due to the smoke-induced attenuation of incoming solar radiation were estimated. The most intensive smoke generation in the atmosphere was observed on August 7–9, 2010, when the maximum aerosol optical thickness amounted to more than 4.0 at a wavelength of 550 nm. In this case, the albedo of single aerosol scattering amounted to ∼0.95–0.96 and the asymmetry factor amounted to ∼0.69–0.70. The maximum shortwave radiative forcing of aerosol amounted to about −360 W/m2 for the land surface and almost −150 W/m2 for the atmospheric upper boundary. During the period of intensive smoke generation, the cooling of the atmospheric surface layer over daylight hours (12 h) amounted, on average, to ∼6°C. The power character of the dependence of the shortwave radiative forcing of aerosol for the land surface on aerosol optical thickness up to its values exceeding 4.0, which was revealed earlier on the basis of data on aerosol optical thickness (up to 1.5) obtained at the OIAP ZSS during the summer forest and peatbog fires of 2002 in the region of Moscow, was supported.  相似文献   

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