scholarly journals An Overview of a Nested Watershed Study in Arctic Alaska

2000 ◽  
Vol 31 (4-5) ◽  
pp. 245-266 ◽  
Author(s):  
D.L. Kane ◽  
L.D. Hinzman ◽  
J.P. McNamara ◽  
Z. Zhang ◽  
C.S. Benson
Keyword(s):  
Coastal Plain ◽  
Summer Precipitation ◽  
Summer Rainfall ◽  
The North ◽  
High Soil Moisture ◽  
Arctic Alaska ◽  
North Slope Of Alaska ◽  
Kuparuk River ◽  
High Runoff ◽  
Circumpolar Arctic

The hydrology of a nest of three watersheds has been studied since 1992 on the North Slope of Alaska, with some additional data collected at individual sites previously. Hydrologic studies of nested watersheds are rare in the circumpolar arctic. Presented here is a comparison of the variability of important runoff-related processes from the headwater foothills to the low gradient, wetland dominated coastal area. Watersheds studied include Imnavait Creek, Upper Kuparuk River and finally the entire Kuparuk River. Also, runoff data from the low gradient Putuligayuk River, measured earlier (1970-1986), is included. Generally, rainfall constitutes 53 to 67 % of the annual precipitation. Most runoff is generated from the foothills; runoff is normally only generated from the coastal plain during snowmelt. Surface storage is an important process on the coastal plain where vertical processes (precipitation and evapotranspiration) are dominant during the summer. Continuous permafrost produces high soil moisture levels except where there are relatively steep slopes with gravity-induced drainage. Snowmelt results in a nearly saturated active layer with summer moisture levels closely allied with summer precipitation. High runoff ratios prevail during snowmelt and rainfall, except for the summer rainfall-generated runoff of the low gradient Putuligayuk River.

Analysis of the Dominant Spatial Patterns of Summer Precipitation and Circulation Characteristics in Northwest China

2020 ◽  
Author(s):  
liwei liu ◽  
guoyang lu ◽  
dong wei ◽  
danhua li ◽  
xing wang ◽  
...  
Keyword(s):  
North Atlantic ◽  
Summer Precipitation ◽  
Summer Rainfall ◽  
Northwest China ◽  
Diagnostic Methods ◽  
Height Field ◽  
Main Mode ◽  
The North ◽  
Circulation Characteristic ◽  
The North Atlantic

<p>In recent years, the summer rainfall shows an increasing trend in Northwest China. Based on the NCEP/NCAR reanalysis data, the RESST data from NOAA and the precipitation data from 351 meteorological observation stations in Northwest China from 1981-2018, the dominant modes of summer precipitation anomalies, the corresponded circulation characteristic and the main influence systems were analyzed by diagnostic methods. There were three dominant EOF modes about summer rainfall, the first one showed the same anomaly in whole region, the second showed a inverse pattern between the east and west, and the third showed the opposite anomaly between the south and north. The variance contribution of the first mode accounted for 20% and the first mode was represented as the primary mode in the subsequent analysis. The high impact region of circulation which affected the precipitation in Northwest China was the middle and high latitudes area of Eurasia and the subtropical area: for the first mode’s positive phase, the 500hPa height field showed a "+ - +" distribution in the middle latitude of Eurasia, while on the 200hPa wind field, there was an anticyclone near the Ural and a cyclone near Lake Baikal, it also has an anticyclone on the Chinese mainland, this configuration will facilitates the strengthening of westerly jets. The tropical Pacific and the North Atlantic are the main external forcing signals of the circulation pattern: SST characteristics showed that the negative phase of the North Atlantic SST Tripole in spring, from winter of the previous year to summer of the current year, SST of the equatorial Middle East Pacific developed from warm to cold. The distribution of 500 hPa height field corresponding to the main mode of summer precipitation in Northwest China is similar to that of EU remote correlation type. An index(I<sub>Hgt</sub>) was defined to reflect circulation patterns in mid-latitude and subtropical regions, when the index is positive/negative, most of the precipitation in northwest China is more/less. After 2000, the correlation between the two increased significantly. Given the performance of the I<sub>Hgt</sub> index in describing the summer precipitation, it could be used as a good indicator in the monitoring and prediction of the summer precipitation in Northwest China.</p>

scholarly journals Empiric Forecasting of Dominant Modes to Summer Precipitation Anomaly of Northeast Brazil

2020 ◽  
Vol 9 (6) ◽  
pp. 353
Author(s):  
Rodrigo Lins Da Rocha Júnior ◽  
Fabrício Daniel Dos Santos Silva ◽  
Rafaela Lisboa Costa ◽  
Heliofábio Barros Gomes
Keyword(s):  
Rainfall Variability ◽  
Summer Precipitation ◽  
Summer Rainfall ◽  
Precipitation Anomaly ◽  
Linear Regression Models ◽  
Equatorial Atlantic ◽  
Economic Activities ◽  
Climate Forecasting ◽  
The North ◽  
Brazilian Northeast

The main economic activities of the Brazilian Northeast (NEB) are affected by the region's highly variable climate, requiring research into seasonal climate forecasting. In a work we show the results obtained after analysing the relationship between the main modes of NEB rainfall variability and lagged oceanic and atmospheric variable fields, that is, preceding rainfall. Consistent relationships were found between sea surface temperature (SST) in the Equatorial Pacific, Equatorial Atlantic and South Atlantic with NEB rainfall. Rossby wave patterns over the North Pacific that propagate from west to east to the Intertropical Convergence Zone (ITCZ), Walker Cell and Upper Bolivia have also been identified. In this research, the main objective was to identify the physical basis for the construction of linear regression models capable of predicting seasonal summer rainfall in the NEB, from the relationships between predictor-predictor. The adjusted regression model performed well between simulations and observations based on validation metrics and can be reliably indicated for operational climate forecasting systems. 

Nitrogen and phosphorus concentrations and export for the upper Kuparuk River on the North Slope of Alaska in 1980

Hydrobiologia ◽  
1992 ◽  
Vol 240 (1-3) ◽  
pp. 61-69 ◽  
Author(s):  
Bruce J. Peterson ◽  
Teresa Corliss ◽  
Keith Kriet ◽  
John E. Hobbie
Keyword(s):  
North Slope ◽  
Nitrogen And Phosphorus ◽  
The North ◽  
North Slope Of Alaska ◽  
Kuparuk River

scholarly journals Seasonal thaw settlement at drained thermokarst lake basins, Arctic Alaska

2014 ◽  
Vol 8 (3) ◽  
pp. 815-826 ◽  
Author(s):  
L. Liu ◽  
K. Schaefer ◽  
A. Gusmeroli ◽  
G. Grosse ◽  
B. M. Jones ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Active Layer Thickness ◽  
Surface Dynamics ◽  
Thermokarst Lake ◽  
The North ◽  
Arctic Alaska ◽  
North Slope Of Alaska ◽  
Thaw Settlement ◽  
Ground Penetrating ◽  
Lake Basins

Abstract. Drained thermokarst lake basins (DTLBs) are ubiquitous landforms on Arctic tundra lowland. Their dynamic states are seldom investigated, despite their importance for landscape stability, hydrology, nutrient fluxes, and carbon cycling. Here we report results based on high-resolution Interferometric Synthetic Aperture Radar (InSAR) measurements using space-borne data for a study area located on the North Slope of Alaska near Prudhoe Bay, where we focus on the seasonal thaw settlement within DTLBs, averaged between 2006 and 2010. The majority (14) of the 18 DTLBs in the study area exhibited seasonal thaw settlement of 3–4 cm. However, four of the DTLBs examined exceeded 4 cm of thaw settlement, with one basin experiencing up to 12 cm. Combining the InSAR observations with the in situ active layer thickness measured using ground penetrating radar and mechanical probing, we calculated thaw strain, an index of thaw settlement strength along a transect across the basin that underwent large thaw settlement. We found thaw strains of 10–35% at the basin center, suggesting the seasonal melting of ground ice as a possible mechanism for the large settlement. These findings emphasize the dynamic nature of permafrost landforms, demonstrate the capability of the InSAR technique to remotely monitor surface deformation of individual DTLBs, and illustrate the combination of ground-based and remote sensing observations to estimate thaw strain. Our study highlights the need for better description of the spatial heterogeneity of landscape-scale processes for regional assessment of surface dynamics on Arctic coastal lowlands.

scholarly journals Springtime Onset of Isolated Convection Precipitation across the Southeastern United States: Framework and Regional Evolution

2020 ◽  
Vol 148 (3) ◽  
pp. 891-906 ◽  
Author(s):  
Thomas M. Rickenbach ◽  
Rosana Nieto Ferreira ◽  
Hannah Wells
Keyword(s):  
United States ◽  
Coastal Plain ◽  
Summer Precipitation ◽  
South Florida ◽  
Atmospheric Conditions ◽  
Precipitation Regime ◽  
The North ◽  
Onset Timing ◽  
Radar Imagery ◽  
Small Clusters

Abstract This study examines the geographic and temporal characteristics of the springtime transition to the summer precipitation regime of isolated convection in the southeastern (SE) United States during 2009–12, using a high-resolution surface radar-based precipitation dataset. Isolated convection refers herein to isolated elements or small clusters of precipitation in radar imagery less than 100 km in horizontal dimension. Though the SE United States does not have a monsoon climate, it is useful to apply the established framework of monsoon onset to study the timing and regional variation of the onset of the summer isolated convection regime. Overall, isolated convection rain onset in the SE U.S. domain occurs in late May. Onset begins in south Florida in mid-April, continuing nearly simultaneously across the southeastern coastal plain in early to mid-May. In the northern domain, from Virginia to the Ohio Valley, onset generally occurs much later (mid-June to early July) with more variable onset timing. The sharpness of onset timing is most evident in the coastal plain and Florida. Results suggest the hypothesis, to be examined in a forthcoming study, that the timing of isolated convection onset in the spring may be triggered by specific synoptic-scale events within gradual seasonal changes in atmospheric conditions including extratropical cyclone tracks, convective instability, and the westward migration of the North Atlantic subtropical high. This approach may offer a useful framework for evaluating long-term changes in precipitation for subtropical regimes in an observational and modeling context.

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