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1.
V. V. Novotryasov S. P. Zakharkov D. V. Stepanov 《Russian Meteorology and Hydrology》2016,41(8):564-568
The results are presented of hydrological studies in the coastal zone of the Sea of Japan in autumn in different years. It is revealed that the typical density stratification of water is formed there in autumn. The amplitudes are estimated of regular (with the periodicity of tidal harmonic M2) vertical displacements of isotherms in the intermediate layer and maximum values of flow velocity in the surface and bottom layers. It is demonstrated that temperature perturbations are induced at the shelf edge and propagate to the coastal zone with the velocity that is close to the velocity of the first mode of internal gravity waves with the frequency of the tidal harmonic M2. 相似文献
2.
金沙江流域径流变化特性分析 总被引：3，自引：0，他引：3
根据金沙江流域8个控制站的径流资料,分析了流域径流的年内分配特性、年际变化特征、径流的趋势性、突变性和周期性。研究表明,金沙江流域水量充沛,径流年内分配不均匀,年际变化较小,但存在连丰、连枯期;在过去的50年内,年径流呈不显著的增加趋势,1966年和1997年径流发生突变,存在3~5年、9年、17年的周期变化。 相似文献
3.
In the 20th century on the territory of the northern slope of the Greater Caucasus the number of glaciers increased by 245 (or by 19%) and the glaciation area decreased by 849 km2 (or by 52.6%). It is revealed that the increase in the number of glaciers occurred as a result of the disintegration of larger glaciers into smaller parts and as a result of the cutoff of their tributaries, and the decrease in the glaciation area, due to the negative balance of the mass of glaciers. The length of all glaciers decreased by 128–3520 m during that period. It is demonstrated that in 1970–2011 the decrease in the glaciation area occurred with the rate being smaller than in 1895–1970 by 1.6 times that is associated with more favorable climatic conditions in 1970–2011. According to the computations of the climate model by the Main Geophysical Observatory (moderate scenario) for 2011–2099, average annual air temperature will increase by 1.06–2.70°C and the annual amount of precipitation, by 2.09–2.77%. According to the results of computations, the glaciation area in 2011–2099 will reduce by 585 km2 or by 76.5%. In the region under consideration, glaciation with the area of 180 km2 which will be concentrated only in the central part of the Greater Caucasus will maintain by 2099. The glacier runoff will decrease by 74–80%. 相似文献
4.
Presented are the explanations of reasons for the anomalous heat in summer of 2010 in the central area of the European part of Russia. It is demonstrated that this event occurred due to the beating of the solar annual (365 days) and lunar annual (355 days) fluctuations of air temperature. To substantiate this conclusion, the data are given on the synchronization of changes in atmospheric processes with the tidal variations of the Earth??s rotation velocity and on the nature of lunar cycles. Illustrated are the evidences of their existence in air temperature fluctuations. Revealed is the sequence of anomalously hot summer seasons in 1901, 1936 (1938), 1972, and 2010 corroborating the existence of the 35-year period of air temperature beats. Proposed is a mechanism of the impact of luni-solar tides on the air temperature based on the interaction between the gravitational luni-solar tides and the radiation conditions in the atmosphere (caused by the cloudiness amount variations). 相似文献
5.
6.
M. V. Bukharov 《Russian Meteorology and Hydrology》2017,42(1):46-53
The spatiotemporal variability is considered ofthe field of ice rarefaction and compression in the Arctic due to the passage of semidiurnal tidal waves. A simplified method is developed for identification of such fields on the maps of the scattering index (SI) of ice computed from the MTVZA-GYa radiometer data. It is demonstrated that the low and high values of ice SI are ob served at tidal rarefactions and compressions, respectively. The analysis of the maps of extreme values of SI observed in overlapping semidiurnal and diurnal MTVZA-GYa measurements corroborated the existence of semidiurnal periodicity of alternating fields of the Arctic ice rarefaction and compression and revealed no variability in ice SI in the areas where tidal wave phases converge (there the convergence amplitude is minimum). 相似文献
7.
The impact of decadal fluctuations in mean precipitation and temperature on runoff: A sensitivity study over the United States 总被引：4，自引：0，他引：4
The nature of climate variability is such that decadal fluctuations in average temperature (up to 1 °C annually or 2 °C seasonally) and precipitation (approximately 10% annually), have occurred in most areas of the United States during the modern climate record (the last 60 years). The impact of these fluctuations on runoff was investigated, using data from 82 streams across the United States that had minimal human interference in natural flows. The effects of recent temperature fluctuations on streamflow are minimal, but the impact of relatively small fluctuations in precipitation (about 10%) are often amplified by a factor of two or more, depending on basin and climate characteristics. This result is particularly significant with respect to predicted changes in temperature due to the greenhouse effect. It appears that without reliable predictions of precipitation changes across drainage basins, little confidence can be placed in hypothesized effects of the warming on annual runoff. 相似文献
8.
The technology ofthe method of joint probabilities ofthe tidal and residual (de-tided) components developed to estimate the possible sea level fluctuations [1, 10] and modified to calculate rare extreme total sea current velocities [8], is applied to compute ice drift velocity on the northeastern shelf of Sakhalin Island. The initial data are the hourly series of the drift velocity vector obtained from radar observations at Odoptu coastal station (1986-1996, during the whole ice season) and at the Molikpaq drilling platform (in May in 1999, 2000, 2003, 2005, and 2006). The distribution of the tidal component was determined by the prediction of the corresponding series for 19 years that is possible due to the stability of characteristics of the tidal drift. The distribution of the residual component was estimated by combining all de-tided series for the entire time period. The obtained estimates of total ice drift velocities of rare occurrence are in good agreement with those presented in [8] and can be used for designing facilities for the extraction and transportation of hydrocarbons on the northeastern shelf of Sakhalin Island. 相似文献
9.
Short-term variations of the elements representing the Earth's motion around the Sun and its rotation have been analyzed over the last 6000 years using 1-year steps. Their low-frequency part is compared first to the values obtained from a secular theory of the planetary long-term motion showing that they can be considered reliable enough to represent adequately the motion of the Earth over the last 5000 years. Spectral analysis of these values shows that the main periodicities are 2.67, 3.98, 5.26, 5.93, 7.9, 9.8, 11.9, 14.7, 15.8, 29, 42, 61, 122, 165 and 250 years for the eccentricity as well as for the climatic precession, with an additional component at around 930 years for the eccentricity and around 840 years for the climatic precession. Periodicities at 2.67, 3.8, 5.9, 8.0, 9.3, 11.9, 14.7, 18.6, 29, 135, 250 and 840 yr are also shown for the obliquity. Spectral analyses of the daily July mid-month insolation at 65°N show essentially the same periodicities as the climatic precession and the obliquity, i.e. 2.67, 3.98, 5.92, 8.1, 11.9, 15.7, 18.6, 29, 40, 61 and around 900 years. Finally a wider analysis of the insolation pattern was performed related to the large periodicity band of the insolation time series for the solstices and the equinoxes for 7 different latitudes. In equatorial latitudes the insolation variance is largely explained by precession. But precession dominates everywhere with the obliquity signal being stronger at polar latitudes at the solstices. The amplitudes of the insolation change at these frequencies is of the order of 0.2 Wm–2 at the maximum.
Offprint requests to: A Berger 相似文献
10.
把大气和地球看成一个孤立的系统,则此系统之总角动量不改变。从冬到夏地球本身的角动量增加,则同一时期大气的总角动量减少,但是低层大气(从地面到800毫巴)的平均西风环流夏季反而强於冬季,因此作者认为:从冬到夏近地面西风环流的这种加强,可能就是同一期间地转角速加快的原因;同时也可能是夏季大气角动量消耗率较高的原因。 相似文献
11.
We examine long-term streamflow and mass balance data from two Alaskan glaciers located in climatically distinct basins: Gulkana Glacier, a continental glacier located in the Alaska Range, and Wolverine Glacier, a maritime glacier located in the Kenai Mountains. Over the 1966–2011 study interval, both glaciers lost mass, primarily as a result of summer warming, and streamflow increased in both basins. We estimate total glacier runoff via summer mass balance and quantify the fraction of runoff related to annual mass imbalances. In both climates, annual (net) mass balance contributes, on average, less than 20 % of total streamflow, substantially less than the fraction related to summer mass loss (>50 %), which occurs even in years of glacier growth. The streamflow fraction related to changes in annual balance increased significantly only in the continental environment. In the maritime climate, where deep winter snowpacks and frequent rain events drive consistently high runoff, the magnitude of this streamflow fraction was small and highly variable, precluding detection of any existing trend. Furthermore, our findings suggest that glacier mass change is likely to impact total basin water yield, timing of runoff and water quality in the continental environment. However, the impacts of maritime glacier change appear more likely to be limited to water quality and runoff timing. 相似文献
12.
V. G. Konovalov 《Russian Meteorology and Hydrology》2007,32(8):529-537
The variability of the main components of the annual water balance (precipitation, evaporation, glacial alimentation, and dynamic water reserves in the basin) for 1935–1990 is, for the first time, determined for the area where the Zeravshan runoff is formed, higher than hydrological post Dupuli is located. Long-term data on the annual Zeravshan River runoff from an area of 10 200 km2 were derived from the measurements at Dupuli hydrological post. The other water balance components were determined with the help of computation methods. Comparison of the measured and calculated volumes of the annual runoff demonstrated that a relative difference between them is systematic, and as a whole for a computation period it is in the interval from ?0.31 to ?4.78%. The annual balance of accumulation and thawing of solid precipitation on glaciers and in the extraglacial area is also determined in the Zeravshan River basin. A new method for computing and mapping spatial variability of the maximum snowline altitude is developed. 相似文献
13.
L. Kristensen 《Boundary-Layer Meteorology》2002,103(1):163-172
An analysis of cup-anemometer dynamics has been carried out inorder to determine whether the mean-wind velocity can have anegative bias. This would be contrary to the general belief thatcup anemometers always overspeed. Compared to prior analyses, theeffect of a possible nonlinearity of the calibration function isincluded. The conclusion is that neither longitudinal nor lateralvelocity fluctuations can contribute significantly to a negativebias. However, if a cup anemometer has an angular response thatfalls below the ideal cosine response, there will, as demonstratedin the concluding discussion, be a negative contribution from thevertical velocity fluctuations to the total bias, and thiscontribution may even outbalance the positive contributions fromthe longitudinal velocity fluctuations. Concrete evidence of suchexotic cup anemometer behaviour has not been reported in theliterature. 相似文献
14.
Paul R. Hurt Leona Marshall Libby Louis J. Pandolfi Lawrence H. Levine W. A. Van Engel 《Climatic change》1979,2(1):75-78
Analysis of the annual blue crab catch in Chesapeake Bay for the years 1922–1976 shows that there are variations with periods of 18.0, 10.7, and 8.6 years. Analysis of Philadelphia air temperatures shows periods of 17.5, 9.8, and 7.4 years. The periods of 18.0 and 17.5 years agree with the 18.6 year period of the Earth-Moon-Sun tidal force, and the periods of 8.6 and 7.4 years agree with the 8.8 year period of the Earth-Moon-Sun tidal force, within experimental error. The periods of 9.8 and 10.7 years, for the temperatures and crabs, respectively, are probably related to the 10.5 year sunspot cycle within experimental error. 相似文献
15.
Walter W. Immerzeel L. P. H. van Beek M. Konz A. B. Shrestha M. F. P. Bierkens 《Climatic change》2012,110(3-4):721-736
The analysis of climate change impact on the hydrology of high altitude glacierized catchments in the Himalayas is complex due to the high variability in climate, lack of data, large uncertainties in climate change projection and uncertainty about the response of glaciers. Therefore a high resolution combined cryospheric hydrological model was developed and calibrated that explicitly simulates glacier evolution and all major hydrological processes. The model was used to assess the future development of the glaciers and the runoff using an ensemble of downscaled climate model data in the Langtang catchment in Nepal. The analysis shows that both temperature and precipitation are projected to increase which results in a steady decline of the glacier area. The river flow is projected to increase significantly due to the increased precipitation and ice melt and the transition towards a rain river. Rain runoff and base flow will increase at the expense of glacier runoff. However, as the melt water peak coincides with the monsoon peak, no shifts in the hydrograph are expected. 相似文献
16.
Dr. A. Bartzokas Prof. C. C. Repapis Prof. D. A. Metaxas 《Meteorology and Atmospheric Physics》1995,55(1-2):113-123
Summary The mean daily march of pressure (hourly values) for each month of the 96 year period 1894–1989 in Athens, Greece is studied using Fourier analysis. The annual variation of the harmonic parameters (amplitude, time of maximum,x andy-components) is examined. The globally excited 2nd and 3rd harmonics show in general the same behaviour as in other places of the Earth. Similar features show the corresponding parameters of the daily solar radiation march. The first harmonic displays some local characteristics. The long period fluctuations study revealed statistically significant trends in most parameters of the 2nd harmonic, most strikingly the 0.5 h shift in the time of its maximum during the 20th century. Power spectrum analysis showed the existence of a biennial oscillation inB
1, thex-component of the first harmonic, but this oscillation is mainly confined to the second half of the entire period. A periodicity of about 6 years which could be associated to the Southern Oscillation was also found inB
1 while inA
1, they-component, a periodicity close to the 11-year solar cycle and another one close to the nutation of the Earth's axis are present. The lunar tides are too small to be detected by the same methods. However the semilunar tide was revealed to be 10–20 times smaller than the semisolar.With 8 Figures 相似文献
17.
用三年冬半年15个月500毫巴逐日资料,计算写成谱函数形式的角动量涡动输送,研究其周期变化。输送总值(波数k=1—12的总和)盛行准两周的周期,逐年差别不大。k=3波输送值也盛行准两周周期,近于同输送总值同位相,而且负担了50％以上的输送总值。其他波数,k=2盛行26天左右周期,k=4盛行12天左右周期,但这些波的变化幅度比k=3波小得多。初步考察了准两周周期同寒潮的关系。 用解纬圈谱法,选例考察k=3波的槽脊走向和振幅,有同角动量输送准两周变化相应的变化。 最后采用功率谱和交叉谱的分析法,对1976—1977年角动量输送进行统计上处理,得到一些与定性分析相同的结果。 相似文献
18.
J.M. Grove 《Climatic change》2001,48(1):53-82
The "Little Ice Age" was the most recent period during which glaciers extended globally, their fronts oscillating about advanced positions. It is frequently taken as having started in the sixteenth or seventeenth century and ending somewhere between 1850 and 1890, but Porter (1981) pointed out that the "Little Ice Age" may 'have begun at least three centuries earlier in the North Atlantic region than is generally inferred'. The glacial fluctuations of the last millennium have been traced in the greatest detail in the Swiss Alps, where the "Little Ice Age" is now seen as starting with advances in the thirteenth century, and reaching an initial culmination in the fourteenth century. In the discussion here, evidence from Canada, Greenland, Iceland, Spitsbergen and Scandinavia is compared with that from Switzerland. Such comparisons have been facilitated by improved methods of calibrating radiocarbon dates to calendar dates and by increasing availability of evidence revealed during the current retreat phase. It is concluded that the "Little Ice Age" was initiated before the early fourteenth century in regions surrounding the North Atlantic. 相似文献
19.
Jiongxin Xu 《Climatic change》2012,112(2):283-298
Controlled by continental monsoon climate, runoff of the Yellow River shows large temporal variability. How runoff responds
to the changing summer monsoon intensity is important both in theory and in water resources management. The earliest hydrological
observations on the Yellow River started in 1919, and thus, runoff data are available only for the past 90 years. Using data
of the summer monsoon intensity (SMI), the temporal variation of SMI since 1873 and the resultant variation in runoff are
dealt with for the drainage area between Hekouzhen and Longmen, Yellow River basin. At the 128-year scale, the variation of
SMI can be generalized as a trend of decreasing first, then increasing and then decreasing again. At the time scale of 50 years
for which concurrent data are available, the temporal variations in both SMI and precipitation show some decreasing trend.
At the time scale of 80 years for which concurrent data were available, the temporal variations in SMI and natural runoff
also show a decreasing trend. For 5-year moving averages of these variables, the synchronous trend of variation is more obvious.
This fact indicates that the variation in SMI results in the variations in precipitation and runoff in the study area. Based
on data of SMI and natural runoff for the period from 1920 to 2000, a regression equation between the 5-year moving averages
of SMI (SMI5m) and natural runoff (Q
wn,5m) was established, which shows that 72% of the variation in Q
wn,5m can be explained by the variation in SMI5m. Using this regression equation, Q
wn,5m for the period from 1873 to 1919 was reconstructed. At the 128-year scale, the natural runoff from the study area shows a
trend of decreasing first, then increasing and then decreasing again, in response to the similar variation in the summer monsoon
intensity. 相似文献
20.
Maximum Entropy Spectral Analysis of the annual rainfall series for 1887–1976 (90 years) for Massachusetts (northeastern USA.) shows T = 17.8 (very near the 18.6 year luni-solar signal) as the most prominent periodicity. However, it explains only 12% variance. Also, the next prominent periodicity is T = 2.72 years, i.e. in the QBO (Quasi-Biennial Oscillation, T = 2–3 years) region. Also, regular periodicities account for only 50% variance, leaving 50% as a random component. Hence, predictions are unreliable. Roughly, excess rainfall during 1990–1994 and droughts during 1992–2002 are indicated; but occasional years of opposite behavior cannot be ruled out. 相似文献