scholarly journals A New Way to Fingerprint Drivers of Water Cycle Change

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Terri Cook
Keyword(s):  
Atmospheric Circulation ◽  
Large Scale ◽  
Water Cycle ◽  
Tropical Ocean ◽  
Climate Effects ◽  
Ocean Convection

Simulations of tropical ocean convection help distinguish climate effects resulting from large-scale changes in atmospheric circulation from those resulting from higher temperatures.

scholarly journals Cascading climate effects and related ecological consequences during past centuries

2012 ◽  
Vol 8 (3) ◽  
pp. 2041-2073
Author(s):  
B. Naef-Daenzer ◽  
J. Luterbacher ◽  
M. Nuber ◽  
T. Rutishauser ◽  
W. Winkel
Keyword(s):  
Life History ◽  
Atmospheric Circulation ◽  
Large Scale ◽  
Great Tit ◽  
Path Model ◽  
Ice Age ◽  
Ecosystem Structure ◽  
Breeding Phenology ◽  
Climate Effects ◽  
Animal Populations

Abstract. The interface between climate and ecosystem structure and function is incompletely understood, partly because few ecological records start before the recent warming phase. Here, we analyse an exceptional 100-yr long record of the great tit (Parus major) population in Switzerland in relation to climate and habitat phenology. Using path analysis, we demonstrate an uninterrupted cascade of significant influences of the large-scale atmospheric circulation (North-Atlantic Oscillation, NAO, and North-sea – Caspian Pattern, NCP) on habitat and breeding phenology, and further on fitness-relevant life history traits within animal populations. We then apply the relationships of this analysis to reconstruct the circulation-driven component of fluctuations in great tit breeding phenology and population dynamics on the basis of new seasonal NAO and NCP indices back to 1500 AD. According to the path model, the multi-decadal oscillation of the atmospheric circulation likely led to substantial variation in habitat phenology, and consequently, tit population minima during the "Maunder Minimum" (1650–1720) and the Little Ice Age Type Event I (1810–1850). The warming since 1975 was not only related with a quick shift towards earlier breeding, but also with the highest productivity since 1500, and thus, an unprecedented increase of the population. A verification of the structural equation model against two independent data series corroborates that the retrospective model reliably depicts the major long-term NAO/NCP impact on ecosystem parameters. The results suggest a complex cascade of climate effects beginning at a global scale and ending at the level of individual life histories. This sheds light on how large scale climate conditions substantially affect major life-history parameters within a population, and thus influence key ecosystem parameters at the scale of centuries.

scholarly journals Cascading climate effects and related ecological consequences during past centuries

2012 ◽  
Vol 8 (5) ◽  
pp. 1527-1540 ◽  
Author(s):  
B. Naef-Daenzer ◽  
J. Luterbacher ◽  
M. Nuber ◽  
T. Rutishauser ◽  
W. Winkel
Keyword(s):  
Life History ◽  
Atmospheric Circulation ◽  
Structural Equation Model ◽  
Structural Equation ◽  
Large Scale ◽  
Equation Model ◽  
Great Tit ◽  
Ecosystem Structure ◽  
Breeding Phenology ◽  
Climate Effects

Abstract. The interface between climate and ecosystem structure and function is incompletely understood, partly because few ecological records start before the recent warming phase. Here, we analyse an exceptional 100-yr long record of the great tit (Parus major) population in Switzerland in relation to climate and habitat phenology. Using structural equation analysis, we demonstrate an uninterrupted cascade of significant influences of the large-scale atmospheric circulation (North-Atlantic Oscillation, NAO, and North-sea – Caspian Pattern, NCP) on habitat and breeding phenology, and further on fitness-relevant life history traits within great tit populations. We then apply the relationships of this analysis to reconstruct the circulation-driven component of fluctuations in great tit breeding phenology and productivity on the basis of new seasonal NAO and NCP indices back to 1500 AD. According to the structural equation model, the multi-decadal oscillation of the atmospheric circulation likely led to substantial variation in habitat phenology, productivity and consequently, tit population fluctuations with minima during the "Maunder Minimum" (∼ 1650–1720) and the Little Ice Age Type Event I (1810–1850). The warming since 1975 was not only related with a quick shift towards earlier breeding, but also with the highest productivity since 1500, and thus, the impact of the NAO and NCP has contributed to an unprecedented increase of the population. A verification of the structural equation model against two independent data series (1970–2000 and 1750–1900) corroborates that the retrospective model reliably depicts the major long-term NAO/NCP impact on ecosystem parameters. The results suggest a complex cascade of climate effects beginning at a global scale and ending at the level of individual life histories. This sheds light on how large-scale climate conditions substantially affect major life history parameters within a population, and thus influence key ecosystem parameters at the scale of centuries.

scholarly journals Stable isotope compositions of precipitation over Central Asia

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11312
Author(s):  
Junqiang Yao ◽  
Xinchun Liu ◽  
Wenfeng Hu
Keyword(s):  
Central Asia ◽  
Atmospheric Circulation ◽  
Moisture Transport ◽  
Environmental Variables ◽  
Large Scale ◽  
Meteoric Water ◽  
Water Cycle ◽  
East Asian Monsoon ◽  
The Relationship ◽  
Large Scale Atmospheric Circulation

Central Asia is one of the driest regions in the world with a unique water cycle and a complex moisture transport process. However, there is little information on the precipitation δ18O content in Central Asia. We compiled a precipitation δ18O database from 47 meteorological stations across Central Asia to reveal its spatial-temporal characteristics. We determined the relationship between precipitation δ18O and environmental variables and investigated the relationship between δ18O and large-scale atmospheric circulation. The Central Asia meteoric water line was established as δ2H = 7.30 δ18O + 3.12 (R2 = 0.95, n = 727, p < 0.01), and precipitation δ18O ranged from +2‰ to −25.4‰ with a mean of −8.7‰. The precipitation δ18O over Central Asia was related to environmental variables. The δ18O had a significant positive correlation with temperature, and the δ18O-temperature gradient ranged from 0.28‰/°C to 0.68‰/°C. However, the dependence of δ18O on precipitation was unclear; a significant precipitation effect was only observed at the Zhangye and Teheran stations, showing δ18O-precipitation gradients of 0.20‰/mm and −0.08‰/mm, respectively. Latitude and altitude were always significantly correlated with annual δ18O, when considering geographical controls on δ18O, with δ18O/LAT and δ18O/ALT gradients of −0.42‰/° and −0.001‰/m, respectively. But both latitude and longitude were significantly correlated with δ18O in winter. The relationship between δ18O and large-scale atmospheric circulation suggested that the moisture in Central Asia is mainly transported by westerly circulation and is indirectly affected by the Indian monsoon. Meanwhile, the East Asian monsoon may affect the precipitation δ18O content in westerly and monsoon transition regions. These results improve our understanding of the precipitation δ18O and moisture transport in Central Asia, as well as the paleoclimatology and hydrology processes in Central Asia.

Interannual Variability of North American Winter Temperature Extremes and Its Associated Circulation Anomalies in Observations and CMIP5 Simulations

2020 ◽  
Vol 33 (3) ◽  
pp. 847-865 ◽  
Author(s):  
B. Yu ◽  
H. Lin ◽  
V. V. Kharin ◽  
X. L. Wang
Keyword(s):  
North America ◽  
Surface Temperature ◽  
Atmospheric Circulation ◽  
North American ◽  
North Pacific ◽  
Large Scale ◽  
Temperature Extremes ◽  
Temperature Extreme ◽  
Central Canada ◽  
Leading Mode

AbstractThe interannual variability of wintertime North American surface temperature extremes and its generation and maintenance are analyzed in this study. The leading mode of the temperature extreme anomalies, revealed by empirical orthogonal function (EOF) analyses of December–February mean temperature extreme indices over North America, is characterized by an anomalous center of action over western-central Canada. In association with the leading mode of temperature extreme variability, the large-scale atmospheric circulation features an anomalous Pacific–North American (PNA)-like pattern from the preceding fall to winter, which has important implications for seasonal prediction of North American temperature extremes. A positive PNA pattern leads to more warm and fewer cold extremes over western-central Canada. The anomalous circulation over the PNA sector drives thermal advection that contributes to temperature anomalies over North America, as well as a Pacific decadal oscillation (PDO)-like sea surface temperature (SST) anomaly pattern in the midlatitude North Pacific. The PNA-like circulation anomaly tends to be supported by SST warming in the tropical central-eastern Pacific and a positive synoptic-scale eddy vorticity forcing feedback on the large-scale circulation over the PNA sector. The leading extreme mode–associated atmospheric circulation patterns obtained from the observational and reanalysis data, together with the anomalous SST and synoptic eddy activities, are reasonably well simulated in most CMIP5 models and in the multimodel mean. For most models considered, the simulated patterns of atmospheric circulation, SST, and synoptic eddy activities have lower spatial variances than the corresponding observational and reanalysis patterns over the PNA sector, especially over the North Pacific.

INFLUENCE OF LARGE-SCALE ATMOSPHERIC PROCESSES ON SEASONAL RUNOFF OF LARGE SIBERIAN RIVERS

2021 ◽  
pp. 36-47
Author(s):  
L. N. VASILEVSKAYA ◽  
◽  
I. A. LISINA ◽  
D. N. VASILEVSKII ◽  
◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
River Runoff ◽  
Large Scale ◽  
Annual Runoff ◽  
Spring Flood ◽  
Atmospheric Circulation Indices ◽  
Rate Of Increase ◽  
Circulation Indices ◽  
Seasonal Runoff ◽  
Kolyma River

Based on daily runoff volumes of four large Siberian rivers (the Ob, Yenisei, Lena, and Kolyma) for 1936-2018, the regime and changes in the total annual and seasonal runoff are analyzed. High synchronous and asynchronous correlations between monthly river runoff and atmospheric circulation indices of hemispheric and regional scales are revealed. In recent decades, the total annual runoff and its variations have increased (the rate of increase is most pronounced for the Kolyma River). A change in water content within a year is heterogeneous: weak positive trends are characteristic of the spring flood runoff and the summer-autumn period, and a significant increase occurred in the winter months. High correlations with a 1-8-month shift made it possible to identify the most informative regions, the atmospheric circulation over which makes a certain contribution to the variance of river runoff.

Historical changes in fresh water transport from sub-tropical to sub-polar oceans

2021 ◽  
Author(s):  
Taimoor Sohail ◽  
Jan Zika ◽  
Damien Irving ◽  
John Church
Keyword(s):  
Fresh Water ◽  
Climate Model ◽  
Water Cycle ◽  
Tropical Ocean ◽  
Freshwater Transport ◽  
Run Off ◽  
Polar Oceans ◽  
S Curve ◽  
Polar Ocean ◽  
Different Response

&lt;p&gt;Warming-induced global water cycle changes pose a significant threat to biodiversity and humanity. &amp;#160;The atmosphere transports freshwater from the sub-tropical ocean to the tropics and poles in two distinct branches.&amp;#160;The resulting air-sea fluxes of fresh water and river run-off imprint on ocean salinity (S) at different temperatures (T), creating a characteristic `T-S curve' of mean salinity as a function of temperature.&amp;#160;Using a novel tracer-percentile framework, we quantify changes in the observed T-S curve from 1970 to 2014. &amp;#160;The warming ocean has been characterised by freshening tropical and sub-polar oceans and salinifying sub-tropical oceans. Over the 44 year period investigated, a net poleward freshwater transport out of the sub-tropical ocean is quantified, implying an amplification of the net poleward atmospheric freshwater transport.&amp;#160;Historical reconstructions from the 6th Climate Model Intercomparison Project (CMIP6) exhibit a different response, underestimating the peak salinification of the ocean by a factor of 4, and showing a weak freshwater transport &lt;em&gt;into&lt;/em&gt; the sub-polar ocean.&amp;#160;Results indicate this discrepancy between the observations and models may be attributed to consistently biased representations of evaporation and precipitation patterns, which lead to the the weaker amplification seen in CMIP6 models.&lt;/p&gt;

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