scholarly journals Temperature and Wind Climate of the Antarctic Peninsula as Simulated by a High-Resolution Regional Atmospheric Climate Model

2015 ◽  
Vol 28 (18) ◽  
pp. 7306-7326 ◽  
Author(s):  
Jan Melchior van Wessem ◽  
Carleen H. Reijmer ◽  
Willem Jan van de Berg ◽  
Michiel R. van den Broeke ◽  
Alison J. Cook ◽  
...  
Keyword(s):  
High Resolution ◽  
Surface Temperature ◽  
Antarctic Peninsula ◽  
Climate Model ◽  
Katabatic Wind ◽  
Near Surface ◽  
Climate Gradients ◽  
Climate Maps ◽  
The Antarctic ◽  
Regional Atmospheric Climate Model

Abstract The latest polar version of the Regional Atmospheric Climate Model (RACMO2.3) has been applied to the Antarctic Peninsula (AP). In this study, the authors present results of a climate run at 5.5 km for the period 1979–2013, in which RACMO2.3 is forced by ERA-Interim atmospheric and ocean surface fields, using an updated AP surface topography. The model results are evaluated with near-surface temperature and wind measurements from 12 manned and automatic weather stations and vertical profiles from balloon soundings made at three stations. The seasonal cycle of near-surface temperature and wind is simulated well, with most biases still related to the limited model resolution. High-resolution climate maps of temperature and wind showing that the AP climate exhibits large spatial variability are discussed. Over the steep and high mountains of the northern AP, large west-to-east climate gradients exist, while over the gentle southern AP mountains the near-surface climate is dominated by katabatic winds. Over the flat ice shelves, where katabatic wind forcing is weak, interannual variability in temperature is largest. Finally, decadal trends of temperature and wind are presented, and it is shown that recently there has been distinct warming over the northwestern AP and cooling over the rest of the AP, related to changes in sea ice cover.

scholarly journals Recent Near-surface Temperature Trends in the Antarctic Peninsula from Observed, Reanalysis and Regional Climate Model Data

2020 ◽  
Vol 37 (5) ◽  
pp. 477-493
Author(s):  
Deniz Bozkurt ◽  
David H. Bromwich ◽  
Jorge Carrasco ◽  
Keith M. Hines ◽  
Juan Carlos Maureira ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Regional Climate Model ◽  
Antarctic Peninsula ◽  
Climate Model ◽  
Regional Climate ◽  
Model Data ◽  
Near Surface ◽  
Temperature Trends ◽  
The Antarctic

scholarly journals Climate of the Greenland ice sheet using a high-resolution climate model – Part 2: Near-surface climate and energy balance

2010 ◽  
Vol 4 (2) ◽  
pp. 603-639 ◽  
Author(s):  
J. Ettema ◽  
M. R. van den Broeke ◽  
E. van Meijgaard ◽  
W. J. van de Berg
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Climate Model ◽  
Regional Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Katabatic Wind ◽  
Surface Cooling ◽  
Near Surface ◽  
Surface Climate

Abstract. The near-surface climate of the Greenland ice sheet is characterized by persistent katabatic winds and quasi-permanent temperature deficit. Using a high resolution (11 km) regional climate model allows for detailed study of the spatial variability in these phenomena and the underlying atmospheric processes. The near-surface temperature distribution over the ice sheet is clearly affected by elevation, latitude, large scale advection, meso-scale topographic features and the occurrence of summer melt. The lowest annual temperatures of −30.5 °C are found north of the highest elevations of the GrIS, whereas the lowest southern margins are warmest (−3.5 °C). Over the ice sheet, a persistent katabatic wind system develops due to radiative surface cooling and the gently slope of the surface. The strongest wind speeds are seen in the northeast where the strong large scale winds, low cloud cover and concave surface force a continuous supply of cold air, which enhances the katabatic forcing. The radiative cooling of the surface is controlled by the net longwave emission and transport of heat towards the surface by turbulence. In summer this mechanism is much weaker, leading to less horizontal variability in near-surface temperatures and wind speed.

scholarly journals The Relationship between the Southern Hemisphere Annular Mode and Antarctic Peninsula Summer Temperatures: Analysis of a High-Resolution Model Climatology

2008 ◽  
Vol 21 (8) ◽  
pp. 1649-1668 ◽  
Author(s):  
Nicole P. M. van Lipzig ◽  
Gareth J. Marshall ◽  
Andrew Orr ◽  
John C. King
Keyword(s):  
High Resolution ◽  
Surface Temperature ◽  
Southern Hemisphere ◽  
Antarctic Peninsula ◽  
Windward Side ◽  
Ice Shelf ◽  
Near Surface ◽  
Annular Mode ◽  
Surface Mass ◽  
Southern Hemisphere Annular Mode

Abstract The large regional summer warming on the east coast of the northern Antarctic Peninsula (AP), which has taken place since the mid-1960s, has previously been proposed to be caused by a trend in the Southern Hemisphere Annular Mode (SAM). The authors utilize a high-resolution regional atmospheric model climatology (14-km grid spacing) to study the mechanisms that determine the response of the near-surface temperature to an increase in the SAM (ΔT/ΔSAM). Month-to-month variations in near-surface temperature and surface pressure are well represented by the model. It is found that north of ∼68°S, ΔT/ΔSAM is much larger on the eastern (lee) side than on the western (windward) side of the barrier. This is because of the enhanced westerly flow of relatively warm air over the barrier, which warms (and dries) further as it descends down the lee slope. The downward motion on the eastern side of the barrier causes a decrease in surface-mass balance and cloud cover. South of ∼68°S, vertical deflection across the barrier is greatly reduced and the contrast in ΔT/ΔSAM between the east and west sides of the barrier vanishes. In the northeastern part of the AP, the modeled ΔT/ΔSAM distribution is similar to the distribution derived from satellite infrared radiometer data. The region of strongest modeled temperature sensitivity to the SAM is where ice shelf collapse has recently taken place and does not extend farther south over the Larsen-C Ice Shelf.

scholarly journals Improving the detailing of atmospheric processes modelling using the Polar WRF model: a case study of a heavy rainfall event at the Akademik Vernadsky station

2020 ◽  
pp. 26-41
Author(s):  
D. Pishniak ◽  
◽  
B. Beznoshchenko ◽  
Keyword(s):  
Surface Temperature ◽  
Antarctic Peninsula ◽  
Precipitation Amount ◽  
Heavy Precipitation ◽  
Horizontal Resolution ◽  
Precipitation Event ◽  
Heavy Rainfall Event ◽  
In Situ Observation ◽  
Near Surface ◽  
The Antarctic

The Antarctic Peninsula region is of growing interest due to the regional climate change features and related atmospheric circulation patterns. The regional mesoscale atmospheric model Polar Weather Research and Forecasting (WRF) v4.1.1 was used in this research to study a heavy precipitation event over the Ukrainian Antarctic Akademik Vernadsky station region (Antarctic Peninsula). The passage of the cyclone over the Antarctic Peninsula as a typical synoptic process as well as a case of the daily precipitation maximum amount of 2018 were chosen for investigation in this research. The estimation of the modelling quality and downscaling was done by comparing the obtained results with in-situ observation at the Akademik Vernadsky station and cross-domain tracking of average meteorological values and their deviation. The concept of the nested domains allowed to increase the horizontal resolution of the simulated atmosphere up to 1 km and to reproduce the wind regime of this region with high quality. Comparison with measured data showed a significant improvement in wind simulation with increasing of resolution, but worse representation of surface temperature and humidity. The Polar WRF made a general cooling of near surface temperature of 2 °C during the period of simulation and increased precipitation amount by 4.6–8.4 mm (12–21%) on average over the territory relative to the initial data from Global Data Assimilation System. This can be explained by the contribution of noise and imperfection of the model (including static input data of the terrain description). Based on the modelled results, the interaction of wind flow with the mountainous terrain of the Antarctic Peninsula creates a range of complex dynamic effects in the atmosphere. These effects cause local precipitation maxima both over the Peninsula and over the adjacent ocean. These are, respectively, bay-valley areas of increased precipitation and increased precipitation on the crests of shock waves from orographic obstacles. Under certain background wind conditions, the influence of the latter effect can reach the Akademik Vernadsky station and cause the formation of heavy precipitation here.

scholarly journals Melting over the East Antarctic Peninsula (1999–2009): evaluation of a high-resolution regional climate model

2017 ◽  
Author(s):  
Rajashree T. Datta ◽  
Marco Tedesco ◽  
Cecile Agosta ◽  
Xavier Fettweis ◽  
Peter Kuipers Munneke ◽  
...  
Keyword(s):  
High Resolution ◽  
Regional Climate Model ◽  
Spatial Resolution ◽  
Antarctic Peninsula ◽  
Climate Model ◽  
Regional Climate ◽  
Ice Shelf ◽  
Circulation Patterns ◽  
The Antarctic ◽  
Microwave Data

Abstract. Surface melting over the Antarctic Peninsula (AP) plays a crucial role for the stability of ice shelves and dynamics of grounded ice, hence modulating the mass balance in a region of the world which is particularly sensitive to increasing surface temperatures. Understanding the processes that drive melting using surface energy and mass balance models is fundamental to improving estimates of current and future surface melting and associated sea level rise through ice-shelf collapse. This is even more important in view of both the paucity of in-situ measurements in Antarctica generally and the specific challenges presented by the circulation patterns over the Antarctic Peninsula. In this study, we evaluate the regional climate model Modèle Atmosphérique Régionale (MAR) over the Antarctic Peninsula (AP) at a 10 km spatial resolution between 1999 and 2009, a period which coincides with the availability of active microwave data from the QuikSCAT mission. This is the first time that this model, which has been validated extensively over Greenland, has been applied to the Antarctic Peninsula at a high resolution. We compare melt occurrence modeled by MAR with a combination of estimates from passive and active microwave data. Our primary regional focus is the northern East Antarctic Peninsula (East AP), where we evaluate MAR against wind and temperature data collected by three automatic weather stations (AWS). Our results indicate that satellites estimates show greater melt frequency, a larger melt extent, and a quicker expansion to peak melt extent than MAR in the center and east of the Larsen C ice shelf. The difference between the remote sensing and modeled estimates reduces in the north and west of the East AP. Melting in the East AP can be initiated by both sporadic westerly föhn flow over the AP and northerly winds advecting warm air from lower latitudes. To quantify MAR's ability to simulate different circulation patterns that affect melt, we take a unique approach to evaluate melt occurrence (using satellite data) and concurrent temperature biases associated with specific wind direction biases using AWS data over the Larsen Ice Shelf. Our results indicate that although MAR shows an overall warm bias, it also shows fewer warm, strong westerly winds than reported by AWS stations, which may lead to an underestimation of melt. The underestimation of föhn flow in the east of the Larsen C may potentially be resolved by removing the hydrostatic assumption in MAR or increasing spatial resolution. The underestimation of southwesterly flow in particular may be reduced by using higher-resolution topography.

scholarly journals A Satellite-Based Climatology of Wind-Induced Surface Temperature Anomalies for the Antarctic

2019 ◽  
Vol 11 (13) ◽  
pp. 1539 ◽  
Author(s):  
Günther Heinemann ◽  
Lukas Glaw ◽  
Sascha Willmes
Keyword(s):  
Surface Temperature ◽  
Climate Model ◽  
Regional Climate ◽  
Weddell Sea ◽  
Model Data ◽  
Ice Shelf ◽  
Near Surface ◽  
Surface Stability ◽  
Ross Ice Shelf ◽  
The Antarctic

It is well-known that katabatic winds can be detected as warm signatures in the surface temperature over the slopes of the Antarctic ice sheets. For appropriate synoptic forcing and/or topographic channeling, katabatic surges occur, which result in warm signatures also over adjacent ice shelves. Moderate Resolution Imaging Spectroradiometer (MODIS) ice surface temperature (IST) data are used to detect warm signatures over the Antarctic for the winter periods 2002–2017. In addition, high-resolution (5 km) regional climate model data is used for the years of 2002 to 2016. We present a case study and a climatology of wind-induced IST anomalies for the Ross Ice Shelf and the eastern Weddell Sea. The IST anomaly distributions show maxima around 10–15K for the slopes, but values of more than 25K are also found. Katabatic surges represent a strong climatological signal with a mean warm anomaly of more than 5K on more than 120 days per winter for the Byrd Glacier and the Nimrod Glacier on the Ross Ice Shelf. The mean anomaly for the Brunt Ice Shelf is weaker, and exceeds 5K on about 70 days per winter. Model simulations of the IST are compared to the MODIS IST, and show a very good agreement. The model data show that the near-surface stability is a better measure for the response to the wind than the IST itself.

scholarly journals Extreme Precipitation and Climate Gradients in Patagonia Revealed by High-Resolution Regional Atmospheric Climate Modeling

2014 ◽  
Vol 27 (12) ◽  
pp. 4607-4621 ◽  
Author(s):  
Jan T. M. Lenaerts ◽  
Michiel R. van den Broeke ◽  
Jan M. van Wessem ◽  
Willem Jan van de Berg ◽  
Erik van Meijgaard ◽  
...  
Keyword(s):  
High Resolution ◽  
Climate Model ◽  
Climate Modeling ◽  
Atmospheric Flow ◽  
Surface Mass ◽  
Climate Gradients ◽  
The Andes ◽  
Ice Field ◽  
Regional Atmospheric Climate Model

Abstract This study uses output of a high-resolution (5.5 km) regional atmospheric climate model to describe the present-day (1979–2012) climate of Patagonia, with a particular focus on the surface mass balance (SMB) of the Patagonian ice fields. Through a comparison with available in situ observations, it is shown that the model is able to simulate the sharp climate gradients in western Patagonia. The southern Andes are an efficient barrier for the prevalent atmospheric flow, generating strong orographic uplift and precipitation throughout the entire year. The model suggests extreme orographic precipitation west of the Andes divide, with annual precipitation rates of >5 to 34 m w.e. (water equivalent), and a clear rain shadow east of the divide. These modeled precipitation rates are supported qualitatively by available precipitation stations and SMB estimates on the ice fields derived from firn cores. For the period 1979–2012, a slight atmospheric cooling at upper ice field elevations is found, leading to a small but insignificant increase in the ice field SMB.

scholarly journals Statistical analysis and time-series models for minimum/maximum temperatures in the Antarctic Peninsula

2006 ◽  
Vol 463 (2077) ◽  
pp. 241-259 ◽  
Author(s):  
Gillian L Hughes ◽  
Suhasini Subba Rao ◽  
Tata Subba Rao
Keyword(s):  
Surface Temperature ◽  
Antarctic Peninsula ◽  
Moving Average ◽  
Extreme Value Distribution ◽  
Likelihood Estimation ◽  
Maximum Temperature ◽  
Correlated Errors ◽  
Near Surface ◽  
Maximum Temperatures ◽  
The Antarctic

It is now widely known that Antarctic air is warming faster than the rest of the world, and the Antarctic Peninsula has experienced major warming over the last 50 years. The monthly mean near surface temperature at the Faraday/Vernadsky station has increased considerably, at a rate of 0.56°C per decade over the year and at 1.09°C per decade over the winter. The increase is not the same over all the stations in the Antarctic region, and the increase is very significant at the Faraday/Vernadsky station. Only at this station are the minimum/maximum monthly temperatures, for the period 1951–2004, separately available, and we believe that the increase in mean surface temperature at this station is mainly due to the increases in minimum temperatures. Therefore, our object in this paper is to study the variations in the minimum/maximum temperatures using a multiple regression model with non-Gaussian correlated errors. By separately analysing the minimum and maximum temperatures, we could clearly identify the source of increase. The average temperature (usually calculated as (max+min)/2) smooths out any variation, and may not be that informative. We model the correlated errors using a linear autoregressive moving average model with innovations, which have an extreme value distribution. We describe the maximum-likelihood estimation methodology and apply this to the datasets described earlier. The methods proposed here can be widely used in other disciplines as well. Our analysis has shown that the increase in the minimum monthly temperatures is approximately 6.7°C over 53 years (1951–2003), whereas we did not find any significant change in the maximum temperature over the same period. We also establish a relationship between the minimum monthly temperatures and ozone levels, and use this model to obtain monthly forecasts for the year 2004 and compare it with the true values available up to December 2004.

scholarly journals An Assessment of ERA5 Reanalysis for Antarctic Near-Surface Air Temperature

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 217
Author(s):  
Jiangping Zhu ◽  
Aihong Xie ◽  
Xiang Qin ◽  
Yetang Wang ◽  
Bing Xu ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Antarctic Peninsula ◽  
Austral Summer ◽  
Correlation Coefficients ◽  
East Antarctica ◽  
West Antarctica ◽  
Austral Spring ◽  
Reanalysis Dataset ◽  
Near Surface ◽  
The Antarctic

The European Center for Medium-Range Weather Forecasts (ECMWF) released its latest reanalysis dataset named ERA5 in 2017. To assess the performance of ERA5 in Antarctica, we compare the near-surface temperature data from ERA5 and ERA-Interim with the measured data from 41 weather stations. ERA5 has a strong linear relationship with monthly observations, and the statistical significant correlation coefficients (p < 0.05) are higher than 0.95 at all stations selected. The performance of ERA5 shows regional differences, and the correlations are high in West Antarctica and low in East Antarctica. Compared with ERA5, ERA-Interim has a slightly higher linear relationship with observations in the Antarctic Peninsula. ERA5 agrees well with the temperature observations in austral spring, with significant correlation coefficients higher than 0.90 and bias lower than 0.70 °C. The temperature trend from ERA5 is consistent with that from observations, in which a cooling trend dominates East Antarctica and West Antarctica, while a warming trend exists in the Antarctic Peninsula except during austral summer. Generally, ERA5 can effectively represent the temperature changes in Antarctica and its three subregions. Although ERA5 has bias, ERA5 can play an important role as a powerful tool to explore the climate change in Antarctica with sparse in situ observations.

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