Seasonal and interannual variations of Amur River discharge and their relationships to large-scale atmospheric patterns and moisture fluxes

2008 ◽  
Vol 113 (D16) ◽  
Author(s):  
Yoshihiro Tachibana ◽  
Kazuhiro Oshima ◽  
Masayo Ogi
Keyword(s):  
River Discharge ◽  
Large Scale ◽  
Interannual Variations ◽  
Amur River ◽  
Moisture Fluxes ◽  
Seasonal And Interannual Variations

scholarly journals Seasonal and interannual variations of MODIS Aqua chlorophyll-a (2003–2017) in the Upper Gulf of Thailand influenced by Asian monsoons

2021 ◽  
Author(s):  
Jutarak Luang-on ◽  
Joji Ishizaka ◽  
Anukul Buranapratheprat ◽  
Jitraporn Phaksopa ◽  
Joaquim I. Goes ◽  
...  
Keyword(s):  
El Niño ◽  
River Discharge ◽  
El Nino ◽  
Gulf Of Thailand ◽  
Interannual Variations ◽  
La Nina ◽  
Seasonal And Interannual Variations ◽  
East West ◽  
Low Precipitation ◽  
Upper Gulf Of Thailand

AbstractSeasonal and interannual variations of chlorophyll-a (chl-a) in the upper Gulf of Thailand (uGoT) were obtained using new regionally tuned algorithms applied to Moderate Resolution Imaging Spectroradiometer-Aqua. This long time-series (2003–2017) data were analyzed in the context of variations in environmental conditions associated with the Southeast Asian Monsoon. Chl-a distribution patterns were distinct for the non-monsoon (NOM), southwest-monsoon (SWM), and northeast-monsoon (NEM) seasons. During the SWM/NEM, high/low chl-a concentrations were associated with high/low precipitation and river discharge. During the NOM chl-a concentrations were generally low, because of low precipitation. In general, chl-a variability was tightly coupled to discharge from the Chao Phraya and Tha Chin rivers. Chl-a concentrations were generally higher in the north, but chl-a accumulation in the east/west of the uGoT could be linked to piling of freshwater to the east/west during the SWM/NEM caused by changes in wind direction and the reversal of currents. Interannual changes in chl-a were attributed to El Niño-Southern Oscillation (ENSO) rather than Indian Ocean Dipole (IOD) driven changes in precipitation, river discharge, and wind patterns. During the SWM, positive/negative chl-a anomalies coincided with high/low precipitation and river discharge during La Niña/El Niño. During the NEM, positive/negative chl-a anomaly coincided with high/low river discharge and strong/weak wind during La Niña/El Niño. Meanwhile, during NOM, positive chl-a anomaly could be attributed to anomalous high wind speed and precipitation during El Niño.

Influences of River Discharge Variation and Tidal Asymmetry on the Spatial Evolution of the Turbidity Maximum Zone in Yangtze Estuary

2020 ◽  
Author(s):  
Ping Dong ◽  
Huabin Shi
Keyword(s):  
River Discharge ◽  
Yangtze Estuary ◽  
Turbidity Maximum ◽  
Tidal Range ◽  
Tidal Asymmetry ◽  
Interannual Variations ◽  
The South ◽  
Turbidity Maximum Zone ◽  
Averaged Model ◽  
Seasonal And Interannual Variations

<p>The Yangtze estuary is characterized by its extremely high suspended sediment concentration (SSC) and the extensive turbidity maximum zone (TMZ). The estuary is physically forced by an upstream river discharge seasonally varying in a wide range of 6000 – 92000 m3/s and semidiurnal-diurnal mixed tides with the tidal range up to 5 m. The influences of the seasonal and interannual variations in the upstream river discharge and the tidal asymmetry on the location of the Yangtze TMZ are numerically investigated with a two-dimensional depth-averaged model. Sensitivities of SSC and hence the location of TMZ to the bottom shear stress, bed erodibility, and the sediment settling velocity are studied. The spatial and temporal evolutions of the TMZ position in the cases of various upstream river discharges with different monthly, seasonal and interannual variations are simulated and discussed. The effects of the M2/M4-induce tidal asymmetry on the TMZ position and those of the interactions between the eight main astronomical tides (M2, S2, N2, K2, K1, O1, P1, and Q1) are compared. It is shown that the M2/M4-induce tidal asymmetry plays a critical role in the formulation of TMZ in the downstream of the South Branch of Yangtze estuary, while the interactions between the eight main astronomical tides have more significant effects on the TMZ location in other areas of Yangtze estuary such as the South and the North Passages.</p>

scholarly journals Large-scale patterns of river inputs in southwestern Europe: seasonal and interannual variations and potential eutrophication effects at the coastal zone

2012 ◽  
Vol 113 (1-3) ◽  
pp. 481-505 ◽  
Author(s):  
Estela Romero ◽  
Josette Garnier ◽  
Luis Lassaletta ◽  
Gilles Billen ◽  
Romain Le Gendre ◽  
...  
Keyword(s):  
Coastal Zone ◽  
Large Scale ◽  
Interannual Variations ◽  
Seasonal And Interannual Variations

Soil Moisture Deficits in South-Central Sweden

1989 ◽  
Vol 20 (2) ◽  
pp. 109-122 ◽  
Author(s):  
Lotta Andersson
Keyword(s):  
Soil Moisture ◽  
Field Capacity ◽  
Interannual Variations ◽  
Neutron Probe ◽  
South Central ◽  
Normal Ranges ◽  
Moisture Fluxes ◽  
In The Beginning ◽  
Probe Measurements ◽  
Different Parts

Some commonly used assumptions about climatically induced soil moisture fluxes within years and between different parts of a region were challenged with the help of a conceptual soil moisture model. The model was optimised against neutron probe measurements from forest and grassland sites. Five 10 yrs and one 105 yrs long climatic records, from the province of Östergötland, situated in south-central Sweden, were used as driving variables. It was concluded that some of the tested assumptions should not be taken for granted. Among these were the beliefs that interannual variations of soil moisture contents can be neglected in the beginning of the hydrological year and that soils usually are filled up to field capacity after the autumn recharge. The calculated climatic induced dryness was estimated to be rather insensitive to the choice of climatic stations within the region. Monthly ranges of soil moisture deficits (1883-1987) were shown to be skewed and it is therefore recommended to use medians and standard deviations in statistical analyses of “normal” ranges of soil moisture deficits.

scholarly journals Hydrology influences breeding time in the white-throated dipper

BMC Ecology ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Anna L. K. Nilsson ◽  
Thomas Skaugen ◽  
Trond Reitan ◽  
Jan Henning L’Abée-Lund ◽  
Marlène Gamelon ◽  
...  
Keyword(s):  
Climate Change ◽  
River Discharge ◽  
Large Scale ◽  
Time Window ◽  
River System ◽  
Open Water ◽  
Local Conditions ◽  
Environmental Indices ◽  
Groundwater Levels ◽  
Breeding Time

Abstract Background Earlier breeding is one of the strongest responses to global change in birds and is a key factor determining reproductive success. In most studies of climate effects, the focus has been on large-scale environmental indices or temperature averaged over large geographical areas, neglecting that animals are affected by the local conditions in their home ranges. In riverine ecosystems, climate change is altering the flow regime, in addition to changes resulting from the increasing demand for renewable and clean hydropower. Together with increasing temperatures, this can lead to shifts in the time window available for successful breeding of birds associated with the riverine habitat. Here, we investigated specifically how the environmental conditions at the territory level influence timing of breeding in a passerine bird with an aquatic lifestyle, the white-throated dipper Cinclus cinclus. We relate daily river discharge and other important hydrological parameters, to a long-term dataset of breeding phenology (1978–2015) in a natural river system. Results Dippers bred earlier when winter river discharge and groundwater levels in the weeks prior to breeding were high, and when there was little snow in the catchment area. Breeding was also earlier at lower altitudes, although the effect dramatically declined over the period. This suggests that territories at higher altitudes had more open water in winter later in the study period, which permitted early breeding also here. Unexpectedly, the largest effect inducing earlier breeding time was territory river discharge during the winter months and not immediately prior to breeding. The territory river discharge also increased during the study period. Conclusions The observed earlier breeding can thus be interpreted as a response to climate change. Measuring environmental variation at the scale of the territory thus provides detailed information about the interactions between organisms and the abiotic environment.

scholarly journals Seasonal and interannual variations of top-of-atmosphere irradiance and cloud cover over polar regions derived from the CERES data set

2006 ◽  
Vol 33 (19) ◽  
Author(s):  
Seiji Kato ◽  
Norman G. Loeb ◽  
Patrick Minnis ◽  
Jennifer A. Francis ◽  
Thomas P. Charlock ◽  
...  
Keyword(s):  
Cloud Cover ◽  
Polar Regions ◽  
Interannual Variations ◽  
Data Set ◽  
Seasonal And Interannual Variations

scholarly journals Cryospheric Impacts of Soviet River Diversion Schemes

1984 ◽  
Vol 5 ◽  
pp. 61-68 ◽  
Author(s):  
T. Holt ◽  
P. M. Kelly ◽  
B. S. G. Cherry
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
River Discharge ◽  
Large Scale ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
Ice Concentration ◽  
The Arctic Ocean ◽  
The Impact

Soviet plans to divert water from rivers flowing into the Arctic Ocean have led to research into the impact of a reduction in discharge on Arctic sea ice. We consider the mechanisms by which discharge reductions might affect sea-ice cover and then test various hypotheses related to these mechanisms. We find several large areas over which sea-ice concentration correlates significantly with variations in river discharge, supporting two particular hypotheses. The first hypothesis concerns the area where the initial impacts are likely to which is the Kara Sea. Reduced riverflow is associated occur, with decreased sea-ice concentration in October, at the time of ice formation. This is believed to be the result of decreased freshening of the surface layer. The second hypothesis concerns possible effects on the large-scale current system of the Arctic Ocean and, in particular, on the inflow of Atlantic and Pacific water. These effects occur as a result of changes in the strength of northward-flowing gradient currents associated with variations in river discharge. Although it is still not certain that substantial transfers of riverflow will take place, it is concluded that the possibility of significant cryospheric effects and, hence, large-scale climate impact should not be neglected.

scholarly journals Interannual dynamics in intensity of mesoscale hydroxyl nightglow variations over Almaty

2018 ◽  
Vol 4 (2) ◽  
pp. 63-68 ◽  
Author(s):  
А. Попов ◽  
A. Popov ◽  
Николай Гаврилов ◽  
Nikolay Gavrilov ◽  
А. Андреев ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Emission Intensity ◽  
Rotational Temperature ◽  
Internal Gravity Waves ◽  
Average Intensity ◽  
Interannual Variations ◽  
Average Temperature ◽  
Monthly Average ◽  
Seasonal And Interannual Variations

The method of digital difference filters is applied to the data analysis of SATI observations of hydroxyl nightglow intensity and rotational temperature at altitudes 85–90 km over Almaty (43°03' N, 76°58' E), Kazakhstan, in 2010–2017. We examine seasonal and interannual variations in monthly average values and standard deviations of variations with periods 0.4–5.4 hrs, which may be associated with internal gravity waves in the mesopause region. The monthly average temperature near the mesopause has a maximum in winter and a minimum in June. The monthly average intensity has an additional maximum in June. Standard deviation of mesoscale rotational temperature variations and characteristics of internal gravity waves are maximum in spring and autumn. The spring maximum of mesoscale OH emission intensity variations is shifted to June. Interannual variations and multi-year trends of OH rotational temperature and emission intensity may differ in detail. This may be connected with seasonal and long-term variations in the complex system of the photochemical processes, which produce the OH nightglow.

Moisture fluxes in the tropics dominated by deep convection up to near tropical tropopause levels

2021 ◽  
Author(s):  
Maximilien Bolot ◽  
Stephan Fueglistaler
Keyword(s):  
Large Scale ◽  
Deep Convection ◽  
Tropical Tropopause Layer ◽  
Tropical Tropopause ◽  
Convective Scale ◽  
Moisture Fluxes ◽  
Global Impacts ◽  
Observational Estimate ◽  
Cold Point ◽  
Open Question

<p>The role played by tropical storms in the tropical tropopause layer (TTL), the transitional layer regulating the flux into the stratosphere of trace gases affecting radiation and the ozone layer, has been a long-standing open question. Progress has been slow because of computational limitations and challenging conditions for measurements and most numerical studies have used simulations over limited domains whose results must be upscaled to the tropical surface to infer global impacts. We compute the first global observational estimate of the convective ice flux at near tropical tropopause levels by using spaceborne lidar measurements from CALIOP. The calculation uses a method to convert from lidar extinction to sedimenting ice flux and uses error propagation to provide margins of uncertainty. We show that, at any given level in the TTL, the sedimenting ice flux exceeds the inflow of vapor computed from ERA5 reanalysis, revealing additional ice transport and allowing to deduce the advective ice flux as a function of altitude. The contribution to this flux of large-scale motions (resolved by ERA5) is computed and the residual is hypothesized to represent the flux of ice on the convective scale. Results show without ambiguity that the upward ice flux in deep convection dominates moisture transport up to close to the level of the cold point tropopause.</p>

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