scholarly journals Effect of western U.S. snow cover on climate

2001 ◽  
Vol 32 ◽  
pp. 82-86 ◽  
Author(s):  
Susan Marshall ◽  
Robert J. Oglesby ◽  
Anne W. Nolin
Keyword(s):  
Snow Cover ◽  
Thermal Effects ◽  
Climate Model ◽  
Regional Climate ◽  
Sea Surface ◽  
System Response ◽  
Initial State ◽  
Climate Anomalies ◽  
Ensemble Simulations ◽  
Sensitivity Studies

AbstractThe purpose of this study is to identify characterize and quantify local, regional and remote effects of snow cover on western U. S. climate and water resources. An ensemble of predictability and sensitivity studies was made with the U.S. National Center for Atmospheric Research (NCAR) Community Climate Model, version 3 (CCM3) to investigate the relative roles of snow-cover anomalies and initial atmospheric states in the subsequent accumulation and ablation seasons. The suite of model experiments focuses on the direct effect of snow on regional climate anomalies and ultimately will be used to examine the lagged effect of anomalous snow cover on the climate. The set of ensemble simulations presented here looks at the climate-system response to anomalously high and low snow cover at the start of the ablation season over the western U.S.A. These current results suggest that the initial state of snow cover is more important than the initial state of the atmosphere or of sea-surface temperatures because of direct thermal effects on the surface and subsequent indirect, dynamical effects on the atmospheric circulation.

scholarly journals Characteristics of convective snow bands along the Swedish east coast

2017 ◽  
Vol 8 (1) ◽  
pp. 163-175 ◽  
Author(s):  
Julia Jeworrek ◽  
Lichuan Wu ◽  
Christian Dieterich ◽  
Anna Rutgersson
Keyword(s):  
Regional Climate Model ◽  
East Coast ◽  
Climate Model ◽  
Regional Climate ◽  
Open Water ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Sea Surface ◽  
Precipitation Rate ◽  
Shallow Convection

Abstract. Convective snow bands develop in response to a cold air outbreak from the continent or the frozen sea over the open water surface of lakes or seas. The comparatively warm water body triggers shallow convection due to increased heat and moisture fluxes. Strong winds can align with this convection into wind-parallel cloud bands, which appear stationary as the wind direction remains consistent for the time period of the snow band event, delivering enduring snow precipitation at the approaching coast. The statistical analysis of a dataset from an 11-year high-resolution atmospheric regional climate model (RCA4) indicated 4 to 7 days a year of moderate to highly favourable conditions for the development of convective snow bands in the Baltic Sea region. The heaviest and most frequent lake effect snow was affecting the regions of Gävle and Västervik (along the Swedish east coast) as well as Gdansk (along the Polish coast). However, the hourly precipitation rate is often higher in Gävle than in the Västervik region. Two case studies comparing five different RCA4 model setups have shown that the Rossby Centre atmospheric regional climate model RCA4 provides a superior representation of the sea surface with more accurate sea surface temperature (SST) values when coupled to the ice–ocean model NEMO as opposed to the forcing by the ERA-40 reanalysis data. The refinement of the resolution of the atmospheric model component leads, especially in the horizontal direction, to significant improvement in the representation of the mesoscale circulation process as well as the local precipitation rate and area by the model.

scholarly journals Precipitation and snow cover in the Himalaya: from reanalysis to regional climate simulations

2013 ◽  
Vol 17 (10) ◽  
pp. 3921-3936 ◽  
Author(s):  
M. Ménégoz ◽  
H. Gallée ◽  
H. W. Jacobi
Keyword(s):  
Snow Cover ◽  
Climate Model ◽  
Regional Climate ◽  
Rain Gauge ◽  
Snow Accumulation ◽  
The Tibetan Plateau ◽  
Monsoon Period ◽  
Medium Range Weather Forecast ◽  
Snow Cover Extent ◽  
The Himalaya

Abstract. We applied a Regional Climate Model (RCM) to simulate precipitation and snow cover over the Himalaya, between March 2000 and December 2002. Due to its higher resolution, our model simulates a more realistic spatial variability of wind and precipitation than those of the reanalysis of the European Centre of Medium range Weather Forecast (ECMWF) used as lateral boundaries. In this region, we found very large discrepancies between the estimations of precipitation provided by reanalysis, rain gauges networks, satellite observations, and our RCM simulation. Our model clearly underestimates precipitation at the foothills of the Himalaya and in its eastern part. However, our simulation provides a first estimation of liquid and solid precipitation in high altitude areas, where satellite and rain gauge networks are not very reliable. During the two years of simulation, our model resembles the snow cover extent and duration quite accurately in these areas. Both snow accumulation and snow cover duration differ widely along the Himalaya: snowfall can occur during the whole year in western Himalaya, due to both summer monsoon and mid-latitude low pressure systems bringing moisture into this region. In Central Himalaya and on the Tibetan Plateau, a much more marked dry season occurs from October to March. Snow cover does not have a pronounced seasonal cycle in these regions, since it depends both on the quite variable duration of the monsoon and on the rare but possible occurrence of snowfall during the extra-monsoon period.

scholarly journals Evaluation of CLASS Snow Simulation over Eastern Canada

2017 ◽  
Vol 18 (5) ◽  
pp. 1205-1225 ◽  
Author(s):  
Diana Verseghy ◽  
Ross Brown ◽  
Libo Wang
Keyword(s):  
Snow Cover ◽  
Land Surface ◽  
Snow Water Equivalent ◽  
Climate Model ◽  
Regional Climate ◽  
Eastern Canada ◽  
Fractional Snow Cover ◽  
Forest Regions ◽  
Snow Water ◽  
Snow Model

Abstract The Canadian Land Surface Scheme (CLASS), version 3.6.1, was run offline for the period 1990–2011 over a domain centered on eastern Canada, driven by atmospheric forcing data dynamically downscaled from ERA-Interim using the Canadian Regional Climate Model. The precipitation inputs were adjusted to replicate the monthly average precipitation reported in the CRU observational database. The simulated fractional snow cover and the surface albedo were evaluated using NOAA Interactive Multisensor Snow and Ice Mapping System and MODIS data, and the snow water equivalent was evaluated using CMC, Global Snow Monitoring for Climate Research (GlobSnow), and Hydro-Québec products. The modeled fractional snow cover agreed well with the observational estimates. The albedo of snow-covered areas showed a bias of up to −0.15 in boreal forest regions, owing to neglect of subgrid-scale lakes in the simulation. In June, conversely, there was a positive albedo bias in the remaining snow-covered areas, likely caused by neglect of impurities in the snow. The validation of the snow water equivalent was complicated by the fact that the three observation-based datasets differed widely. Also, the downward adjustment of the forcing precipitation clearly resulted in a low snow bias in some regions. However, where the density of the observations was high, the CLASS snow model was deemed to have performed well. Sensitivity tests confirmed the satisfactory behavior of the current parameterizations of snow thermal conductivity, snow albedo refreshment threshold, and limiting snow depth and underlined the importance of snow interception by vegetation. Overall, the study demonstrated the necessity of using a wide variety of observation-based datasets for model validation.

High Resolution Sensitivity Studies with the Regional Climate Model CCLM in the Alpine Region

2008 ◽  
Vol 17 (4) ◽  
pp. 467-476 ◽  
Author(s):  
Martin Suklitsch ◽  
Andreas Gobiet ◽  
Armin Leuprecht ◽  
Christoph Frei
Keyword(s):  
High Resolution ◽  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Alpine Region ◽  
Sensitivity Studies

scholarly journals High-resolution sensitivity studies with the regional climate model COSMO-CLM

2009 ◽  
Vol 18 (5) ◽  
pp. 543-557 ◽  
Author(s):  
Cathérine Schädler Meissner ◽  
Hans-Jürgen Feldmann Panitz ◽  
Christoph Kottmeier
Keyword(s):  
High Resolution ◽  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Sensitivity Studies

scholarly journals Recent Changes in the Annual Mean Regional Hadley Circulation and Their Impacts on South America

2015 ◽  
Vol 2015 ◽  
pp. 1-22 ◽  
Author(s):  
Ana Carolina Vasques Freitas ◽  
Tércio Ambrizzi
Keyword(s):  
South America ◽  
Climate Model ◽  
Regional Climate ◽  
Model Performance ◽  
Hadley Circulation ◽  
Sea Surface ◽  
Westerly Winds ◽  
Positive Correlations ◽  
Poleward Expansion

This work employs the regional climate model RegCM4 and observational datasets to investigate the impacts of changes in the intensity and poleward edge of regional HC over South America (HCSA) on the patterns of wind, geopotential height, precipitation, and temperature during the period 1996–2011. Significant trends of HCSA intensification and poleward expansion are found during the period analyzed. To evaluate the effects of these changes over SA, two composites, representing the intensification and poleward expansion cases, are examined separately. Significant correlations are seen between the temperature, zonal wind, and the HCSA intensity over the northern, central, and southern regions of SA and South Atlantic. Results show that, in both composites, regions with anomalous easterly (westerly) winds coming from (towards) the Atlantic Ocean have negative (positive) correlations with the HCSA intensity and poleward edge. The model performance varies regionally and the southern SA region exhibits better agreement with the observations. The role of the sea surface temperatures in driving the changes in the HCSA is examined. Notable similarity is found in the results for the two cases analyzed, which could indicate that, in most cases, the changes in the intensity and poleward edge of the HCSA are occurring simultaneously.

scholarly journals Northern Hemisphere Snow Cover, Indo-Pacific SSTs, and Recent Trend as Statistical Predictors of Seasonal North American Temperature

2015 ◽  
Vol 54 (1) ◽  
pp. 58-68 ◽  
Author(s):  
D. S. Wilks
Keyword(s):  
Snow Cover ◽  
North American ◽  
Recent Trend ◽  
Warming Trend ◽  
Sea Surface ◽  
Training Data ◽  
Lead Times ◽  
Maximum Covariance Analysis ◽  
Climate Anomalies ◽  
Recent Climate

AbstractMaximum covariance analysis (MCA) forecasts of gridded seasonal North American temperatures are computed for January–March 1991 through February–April 2014, using as predictors Indo-Pacific sea surface temperatures (SSTs), Eurasian and North American snow-cover extents, and a representation of recent climate nonstationarity, individually and in combination. The most consistent contributor to overall forecast skill is the representation of the ongoing climate warming, implemented by adding the average of the most recent 15 years’ predictand data to the climate anomalies computed by the MCA. For winter and spring forecasts at short (0–1 month) lead times, best forecasts were achieved using the snow-extent predictors together with this representation of the warming trend. The short available period of record for the snow data likely limits the skill that could be achieved using these predictors, as well as limiting the length of the SST training data that can be used simultaneously.

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