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1.
Historical dates of ice-affected flows for 16 rural, unregulated rivers in northern New England, USA were analyzed. The total annual days of ice-affected flow decreased significantly (p < 0.1) over the 20th century at 12 of the 16 rivers. On average, for the nine longest-record rivers, the total annual days of ice-affected flow decreased by 20 days from 1936 to 2000, with most of the decrease occurring from the 1960s to 2000. Four of the 16 rivers had significantly later first dates of ice-affected flow in the fall. Twelve of the 16 rivers had significantly earlier last dates of ice-affected flow in the spring. On average, the last dates became earlier by 11 days from 1936 to 2000 with most of the change occurring from the 1960s to 2000. The total annual days of ice-affected flow were significantly correlated with November through April air temperatures (r = −0.70) and with November through April precipitation (r = −0.52). The last spring dates were significantly correlated with March through April air temperatures (r = −0.73) and with January through April precipitation (r = −0.37). March mean river flows increased significantly at 13 of the 16 rivers in this study.The U.S. Government right to retain a non-exclusive royalty-free license in and to any copyright is acknowledged. 相似文献
2.
E. V. Shevnina 《Russian Meteorology and Hydrology》2009,34(1):51-57
Multi-year characteristics of the beginning of spring floods and their peak flow observed at the stream gauges located in the estuary sections of the Ob and Yenisei rivers in the period from 1936 to 2003 were obtained in this work. For most of stream gauges, significant correlation between these characteristic dates and dates when the accumulated positive temperatures (observed at the meteorological stations located in the middle parts of the catchments) reached 30 and 40°C was revealed. A great percentage of successful forecasts issued by using the multiple regression equations (78–86%) allow recommending using the obtained relationships for long-range forecasting of dates of the spring flood beginning and its peaks in the estuary sections of the Ob and Yenisei rivers with a 20–24-days lead time. 相似文献
3.
Long-term variations of ice formation dates are studied using the long (more than 100 years) series of observations of ice regime on the rivers of the Votkinsk Reservoir catchment. Proposed is the methodological approach to assessing the long-term variability of these dates using both parametric and nonparametric statistical criteria. 相似文献
4.
Glenn A. Hodgkins 《Climatic change》2013,119(3-4):705-718
Many studies have shown that lake ice-out (break-up) dates in the Northern Hemisphere are useful indicators of late winter/early spring climate change. Trends in lake ice-out dates in New England, USA, were analyzed for 25, 50, 75, 100, 125, 150, and 175 year periods ending in 2008. More than 100 years of ice-out data were available for 19 of the 28 lakes in this study. The magnitude of trends over time depends on the length of the period considered. For the recent 25-year period, there was a mix of earlier and later ice-out dates. Lake ice-outs during the last 50 years became earlier by 1.8 days/decade (median change for all lakes with adequate data). This is a much higher rate than for longer historical periods; ice-outs became earlier by 0.6 days/decade during the last 75 years, 0.4 days/decade during the last 100 years, and 0.6 days/decade during the last 125 years. The significance of trends was assessed under the assumption of serial independence of historical ice-out dates and under the assumption of short and long term persistence. Hypolimnion dissolved oxygen (DO) levels are an important factor in lake eutrophication and coldwater fish survival. Based on historical data available at three lakes, 32 to 46 % of the interannual variability of late summer hypolimnion DO levels was related to ice-out dates; earlier ice-outs were associated with lower DO levels. 相似文献
5.
Long-term variability and methods of forecasting dates of ice break-up in the mouth area of the Ob and Yenisei rivers 总被引：1，自引：0，他引：1
Long-term characteristics of the onset dates of spring ice phases at hydrological stations in the mouth areas of the Ob and Yenisei rivers for 1936–2006 are obtained. The correlations are analyzed between these dates and the frequency of different synoptic processes over the Atlantic and Eurasia in the fall-winter months, the dates when the accumulated temperatures at meteorological stations in the middle parts of the river basins reach 5, 10, 20, 30, and 40°C, and the dates of the start of ice drift at the upstream sections of the Yenisei. Prognostic relations are suggested and test forecasts of the onset dates of ice phases are verified. The percentage of correct forecasts was 67–86%, which makes it possible to recommend the relations for using in prognostic practice. The forecast lead time ranges from 3 to 110 days. 相似文献
6.
Variability of Northeast China river break-up date 总被引：5，自引：0，他引：5
This paper investigates the variability of the break-up dates of the rivers in Northeast China from their icebound states for the period of 1957–2005 and explores some potential explanatory mechanisms. Results show that the break-up of the two major rivers(the Heilongjiang River and Songhuajiang River) was about four days earlier,and their freeze-up was about 4–7 days delayed,during 1989–2005 as compared to 1971–1987.This interdecadal variation is evidently associated with the warming trend over the past 50... 相似文献
7.
Juliane Bernhardt Christof Engelhardt Georgiy Kirillin J?rg Matschullat 《Climatic change》2012,112(3-4):791-817
Rising northern hemispheric mean air temperatures reduce the amount of winter lake ice. These changes in lake ice cover must be understood in terms of resulting effects on lake ecosystems. Accurate predictions of lake ice phenology are essential to assess resulting impact. We applied the one-dimensional physical lake model FLake to analyse past variability in ice cover timing, intensity and duration of Berlin-Brandenburg lakes. The observed ice phenology in two lakes in the period 1961–2007 was reconstructed by FLake reasonably well and with higher accuracy than by state-of-the-art linear regression models. Additional modelling results of FLake for 38 Berlin-Brandenburg lakes, observed in the winter of 2008/09, were quite satisfactory and adequately reproduced the effects of varying lake morphology and trophic state. Observations and model results showed that deeper and clearer lakes had more ice-free winters, later ice cover freezing and earlier ice cover thawing dates, resulting in shorter ice-covered periods and fewer ice-covered days than shallow and less clear lakes. The 1947–2007 model hindcasts were implemented using FLake for eight Berlin-Brandenburg lakes without ice phenology observations. Results demonstrated past trends of later ice start and earlier ice end, shorter ice cover duration and an increase in ice-free winters. 相似文献
8.
Ice phenomena terms on the water bodies of Northwestern Russia 总被引：1，自引：0，他引：1
The dependence of ice phenomena (the dates of ice freeze-up and break-up) on the air temperature and geographic factors (geographic
latitude, height above sea level, and average depth and area of lakes) is investigated on the basis of the data of long-term
observations on the water bodies of Northwestern Russia. The regression models with rather high accuracy level are proposed
not requiring a large number of input parameters unlike the deterministic models. 相似文献
9.
Records of hydrologic parameters, especially those parameters that are directly linked to air temperature, were analyzed to
find indicators of recent climate warming in Minnesota, USA. Minnesota is projected to be vulnerable to climate change because
of its location in the northern temperate zone of the globe. Ice-out and ice-in dates on lakes, spring (snowmelt) runoff timing,
spring discharge values in streams, and stream water temperatures recorded up to the year 2002 were selected for study. The
analysis was conducted by inspection of 10-year moving averages, linear regression on complete and on partial records, and
by ranking and sorting of events. Moving averages were used for illustrative purposes only. All statistics were computed on
annual data.
All parameters examined show trends, and sometimes quite variable trends, over different periods of the record. With the exception
of spring stream flow rates the trends of all parameters examined point toward a warming climate in Minnesota over the last
two or three decades. Although hidden among strong variability from year to year, ice-out dates on 73 lakes have been shifting
to an earlier date at a rate of −0.13 days/year from 1965 to 2002, while ice-in dates on 34 lakes have been delayed by 0.75
days/year from 1979 to 2002. From 1990 to 2002 the rates of change increased to −0.25 days/year for ice-out and 1.44 days/year
for ice-in. Trend analyses also show that spring runoff at 21 stream gaging sites examined occurs earlier. From 1964 to 2002
the first spring runoff (due to snowmelt) has occurred −0.30 days/year earlier and the first spring peak runoff −0.23 days/year
earlier. The stream water temperature records from 15 sites in the Minneapolis/St Paul metropolitan area shows warming by
0.11∘C/year, on the average, from 1977 to 2002. Urban development may have had a strong influence. The analysis of spring stream
flow rates was inconclusive, probably because runoff is linked as much to precipitation and land use as to air temperature.
Ranking and sorting of annual data shows that a disproportionately large number of early lake ice-out dates has occurred after
1985, but also between 1940 and 1950; similarly late lake ice-in has occurred more frequently since about 1990. Ranking and
sorting of first spring runoff dates also gave evidence of earlier occurrences, i.e. climate warming in late winter.
A relationship of changes in hydrologic parameters with trends in air temperature records was demonstrated. Ice-out dates
were shown to correlate most strongly with average March air temperatures shifting by −2.0 days for a 1°C increase in March air temperature. Spring runoff dates also show a relationship with March air temperatures; spring runoff
dates shift at a rate of −2.5 days/1°C minimum March air temperature change. Water temperatures at seven river sites in the Minneapolis/St Paul metropolitan area
show an average rise of 0.46°C in river temperature/1°C mean annual air temperature change, but this rate of change probably includes effects of urban development.
In conclusion, records of five hydrologic parameters that are closely linked to air temperature show a trend that suggests
recent climate warming in Minnesota, and especially from 1990 to 2002. The recent rates of change calculated from the records
are very noteworthy, but must not be used to project future parameter values, since trends cannot continue indefinitely, and
trend reversals can be seen in some of the long-term records. 相似文献
10.
鄱阳湖流域综合管理的探索 总被引：15，自引：1，他引：15
在介绍鄱阳湖流域背景和综合管理机构职能,以及相应地方法规的完善和流域总体发展规划编制的基础上,系统地阐述了近20a来流域综合管理的内容与措施,并就取得的成效进行了科学的分析和研究。研究结果认为,近20a来,尤其是进入21世纪以来,针对鄱阳湖流域生态环境恶化与资源开发利用中存在的问题,江西省积极动员各方面的力量,根据《江西省山江湖开发治理总体规划纲要》要求和“五年发展规划”的具体部署,坚持既要金山银山,更要绿水青山;坚持实施可持续发展战略要注重社会、经济和生态环境协调发展,流域管理要注重系统性和综合性,以及以先进技术为依托、因地制宜、试点先行的科学原则,把流域作为一个互相联系的生态经济系统,以开放促开发,治山、治江、治湖和治穷有机结合,持续开展了大规模的保护环境、治理山水、建设美好江西的山江湖开发治理工程的建设和实践,为流域综合治理和区域可持续发展进行了富有成效的探索,取得了可喜的成效。 相似文献
11.
Break-up Dates of Alpine Lakes As Proxy Data for Local and Regional Mean Surface Air Temperatures 总被引：5，自引：1，他引：4
David M. Livingstone 《Climatic change》1997,37(2):407-439
The calendar date of ice break-up on Lej da San Murezzan, a high-altitude (1768 m a.s.l.) lake in the Swiss Alps, has been recorded uninterruptedly since 1832. Based on this record and on shorter, interrupted records from two neighbouring lakes, the potential use of the timing of spring break-up as a proxy for local and regional surface air temperatures in the European Alpine region is investigated. Lej da San Murezzan exhibits an overall trend to earlier thawing (7.6 days per century) comparable to that of lakes in other parts of the Northern Hemisphere. Part of this trend may be due to shifts in mean break-up date around 1857 and 1932. The timing of break-up on all three lakes is strongly related to local and regional surface air temperatures centred on the middle of April and integrated over 4–8 weeks. Three empirical methods of relating break-up date to local air temperature yielded essentially the same proportion of shared variance (about 64%). Comparisons of break-up dates with surface air temperature data from Switzerland, the Netherlands and the United Kingdom suggest that the thawing of Alpine lakes is determined to a large extent by synoptic-scale meteorological processes. The timing of break-up on Lej da San Murezzan also tends to follow an index of global explosive volcanism with a time lag of about two years, volcanically quiescent periods being associated with early break-up, and volcanically active periods with late break-up. This suggests that modulation of incident radiation by stratospheric aerosols of volcanic origin may significantly affect the timing of break-up of high-altitude lakes. 相似文献
12.
以新疆第一次（2000年）和第二次（2011年）湿地资源调查中相同的347块湿地为研究对象,利用3S技术,对CBERS、SPOT5和LandsatTM遥感数据进行调查监测,并结合野外实地验证,比较分析新疆湿地资源的时空变化状况及其原因。结果表明,新疆湿地总面积呈减少的趋势,其中河流湿地和沼泽湿地面积增加,分别增加29162 hm2和17130 hm2,湖泊湿地和人工湿地面积减少,分别减少126618 hm2和19391 hm2;各湿地型中,永久性河流、草本沼泽、森林沼泽和季节性咸水沼泽面积有所增加,洪泛平原、内陆盐沼、永久性 淡水湖、季节性淡水湖、季节性咸水湖和库塘湿地面积减少。新疆湿地面积总变化率-7%,各湿地类型中,面积变化率最大的是湖泊湿地（18%）,呈减少趋势;最小的是沼泽湿地（5%）,呈增加趋势。湿地面积变化的主要原因是气候变化和人类活动。 相似文献
13.
N. A. Bakunov D. Yu. Bol’shiyanov A. S. Makarov 《Russian Meteorology and Hydrology》2010,35(10):673-679
90Sr runoff amounted to 0.22–0.67% of its budget in the catchment; the value is lower for high-latitude rivers running in the zone of frozen and seasonally frozen grounds. The ecological half-period of a decrease in the 90Sr concentration in the river water of Eastern Fennoscandia amounted to 5.9–11.5 years in 1979–1985. The lake waters (Lake Ladoga and Lake Päijänne) were renewed approximately 4–5 times faster than the 90Sr content decreased in these lakes. 相似文献
14.
15.
C. B. Fobes 《Theoretical and Applied Climatology》1949,1(2):138-148
Summary The present author has discussed the ice-clearing dates of Maine lakes from a meteorological standpoint, some years ago [1]. New data have been collected for the larger New Hampshire lakes, namely: Winnipesaukee, Sunapee, First Connecticut, and Second Connecticut. Besides, the 65 year record of Sysladobsis Lake in eastern Maine was added. This paper presents in tabular form the geographical data (Table 1). The average and extreme opening dates and their variability appear in Table 2. The homogeneity of the observational series is discussed. With the aid of the present material it is shown that the difference of the absolute extremes of a certain unit-period approaches a certain limit with increasing length of the period of observation. The relation between difference of the extremes and length of the period is represented analytically for the different lakes. The variations of the coefficient appearing in the equations are discussed for the lake-region in question. The relation mentioned has been applied to climatological problems [2], [3] and is introduced here, perhaps for the first time, into the realm of limnology. Finally, the variations of the clearingdates of the lakes are briefly discussed.
With 2 figures. 相似文献
Zusammenfassung Vor einigen Jahren hat der Verfasser die Daten des Aufgehens von einigen Seen in Maine vom meteorologischen Standpunkt diskutiert [1]. Seitdem wurde auch Material für die größeren Seen von New Hampshire zusammengetragen, und zwar für den Winipesaukee, den Sunapee, den ersten und zweiten Connecticut-See; außerdem konnten Daten für den Sysladobsis-See in Maine hinzugefügt werden, die einen Zeitraum von 65 Jahren umfassen. In Tabelle 1 werden die geographischen Daten der Seen mitgeteilt. Die mittleren und extremen Daten des Aufgehens und ihre Veränderlichkeit erscheinen in Tabelle 2. Die Homogenität der Beobachtungsreihen wird kritisch beleuchtet. An Hand des Materials wird gezeigt, daß die Differenz der absoluten Extreme einer bestimmten Einheitsperiode sich mit wachsender Periodenlänge einer Grenze zu nähern scheint. Die Beziehung zwischen extremen Differenzen und Periodenlängen wird für die verschiedenen Seen analytisch dargestellt. Die Änderungen des in den Gleichungen erscheinenden Koeffizienten werden für das betrachtete Seengebiet erörtert. Die erwähnte Beziehung ist in der Klimatologie verwendet worden [2], [3] und wird hier wohl erstmalig in die Limnologie eingeführt. Schließlich werden die Schwankungen der Daten des Aufgehens der Seen kurz diskutiert.
Résumé Il y a quelques années, l'auteur a traité les dates de dégel de quelques lacs en Maine d'un point de vue météorologique. Depuis, des observations nouvelles ont été recueillies pour les plus grands lacs en New Hampshire. Ce sont: les Lacs Winnipesaukee, Sunapee, le premier et le second Connecticut; de plus, les dates du lac Sysladobsis, Maine, pour 65 années ont été ajoutées. Tableau 1 montre les dates géographiques des lacs. Tableau 2 donne les dates moyennes et extrêmes du dégel et de leur variabilité. La homogénéité des séries d'observations est discutée. A l'aide du nouveau matériel on a montré que la différence des extrêmes absolus d'une certaine unité de periode s'approche d'une limite déterminée en accord avec la longueur de la période d'observation. La relation entre les différences des extrêmes et la longueur de la période est représentée d'une manière analytique pour les différents lacs. La variation du coéfficient montrée dans les équations est discutée concernant la région des lacs mentionnés. Cette relation a été appliquée à des problèmes climatologiques[2], [3] et est introduite ici peut-être pour la première fois dans le domaine de la limnologie. Finalement, la variation des dates du dégel des lacs est brièvement discutée.
With 2 figures. 相似文献
16.
Our analyses partition the relative influence of progressive climate change and large-scale climate drivers that can be associated with the Quasi-Biennial Oscillation (QBO), El Niño Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), solar sunspot cycle, and multi-decadal oscillations on lake ice breakup dates for thirteen Northern Hemisphere lakes. Oscillatory dynamics explain 26 % of the total variance in the time series compared with 15 % for linear trends, leaving 60 % unexplained and likely attributable, in part, to local weather. Significant oscillatory dynamics include frequencies in 2–3 year periods (9.4 % of the total variance), 3–6 year periods (8.2 %), 10–12 year periods (1.6 %) and various multidecadal periods (0.4–1.3 %). All 13 study lakes, although widely scattered in the Northern Hemisphere, had similar oscillatory dynamics and linear trends, emphasizing that global processes influence lake ice breakup locally. We illustrate that while quasi-periodic dynamics associated with large-scale climate drivers are important, they do not mask the clear evidence for progressive climate change. 相似文献
17.
Sapna Sharma John J. Magnuson Gricelda Mendoza Stephen R. Carpenter 《Climatic change》2013,118(3-4):857-870
We investigate the temporal patterns in inter-annual variability in ice breakup dates for Lakes Mendota and Monona, Wisconsin, between 1905 and 2004. We analyze the contributions of long-term trends attributed to climate change, local weather, indices of sunspots, and large-scale climatic drivers, such as the North Atlantic Oscillation (NAO) and El Niňo Southern Ocean Index (ENSO) on time series of lake-ice breakup. The relative importance of the aforementioned explanatory variables was assessed using linear regression and variation partitioning models accounting for cyclic temporal dynamics as represented by Moran Eigenvector Maps (MEM). Model results explain an average of 58 % of the variation in ice breakup dates. A combination of the long-term linear trends, rain and snowfall in the month prior to breakup, air temperature in the winter prior to breakup, cyclic dynamics associated with sunspot numbers, ENSO, and for Lake Mendota, NAO, all significantly influence the timing of ice breakup. Significant cycle lengths were 3.5, 9, 11, and 50 years. Despite their proximity, Lakes Mendota and Monona exhibit differences in how and which explanatory variables were incorporated into the models. Our results indicate that lake ice dynamics are complex in both lakes and multiple interacting processes explain the residuals around the linear warming trends that characterize lake ice records. 相似文献
18.
用天气学方法分析了天津市2002--2005年夏季最大电力负荷过程的天气背景场、气象要素场和人体舒适度指数。结果显示,在电力负荷上升阶段,高空由低压槽转为高压脊,副热带高压逐步北抬,地面气压、气温回升,风力减小;峰值阶段,副热带高压完全控制华北地区,地面均压,最高气温多日维持在35℃以上,综合反映气温、相对湿度和风速的舒适度指数超过1200。当高空槽再次临近,副热带高压南撤退出天津地区,强降水过程出现,气温、气压急剧下降,电力负荷极值过程宣告结束。分析表明,夏季最大电力负荷过程与天气系统的高低空配置、气象要素、舒适度指数存在一定规律性。 相似文献
19.
The POMRad system of computer models is developed using the Princeton Ocean Model (POM) program code. The system enables modeling the radionuclide migration in large nonuniform water bodies (seas, bays, large rivers, and lakes) taking account of the migration of radioactive substances in the water mass-bottom system associated with the migration of radionuclides sorbed on suspended sediments and in solutes. In order to take account of radionucide transport with sediments the POM program code is supplemented with the models describing transport, settling, and resuspension of suspended sediments. The verification was carried out through comparing analytical solutions of simplified problems concerning the content of radionuclides in water, and modeling results. A potential of the POMRad application is demonstrated by an example of simulating the radioactivity transport in marine environment in the case of hypothetical accidents in the Saida and Kola bays. 相似文献
20.
The ten-year mean anomalies of seasonal and annual temperatures were reconstructed on the basis ofhistorical documents of cold events such as severe snowing and freezing of lakes and rivers.The assorted eventswere calibrated with instrumental observations of temperature and transformed into ten-year mean anomalies.The reconstructed temperature series show predominance of cold climate in the first four hundred years of theperiod examined.The centenary seasonal temperature anomalies for the 16th to the 19th century vary between-0.1 and -0.7K.The coldest decades concentrated in the middle of 17th and 19th centuries.It provided theirrefutable evidence of the occurrence of the Little Ice Age in China.The minima of ten-year mean temperatureanomalies ranged about -1.5 to 2.0K in spring and winter.Meanwhile,the variance of ten-year mean tempera-ture was increased by more than 20％ in comparison to the 20th century. 相似文献