Simulation and evaluation of 2-m temperature over Antarctica in polar regional climate model

The European Centre for Medium-Range Weather Forecasts Reanalysis ERA40, National Centers for Environmental Prediction (NCEP) 20th-century reanalysis, and three station observations along an Antarctic traverse from Zhongshan to Dome-A stations are used to assess 2-m temperature simulation skill of a regional climate model. This model (HIRHAM) is from the Alfred Wegener Institute for Polar and Marine Research in Germany. Results show: (1) The simulated multiyear averaged 2-m temperature field pattern is close to that of ERA40 and NCEP; (2) the cold bias relative to ERA40 over all of Antarctic regions is 1.8°C, and that to NCEP reaches 5.1°C; (3) bias of HIRHAM relative to ERA40 has seasonal variation, with a cold bias mainly in the summer, as much as 3.4°C. There is a small inland warm bias in autumn of 0.3°C. Further analysis reveals that the reason for the cold bias of 2-m temperature is that physical conditions of the near-surface boundary layer simulated by HIRHAM are different from observations: (1) During the summer, observations show that near-surface atmospheric stability conditions have both inversions and non-inversions, which is due to the existence of both positive and negative sensible heat fluxes, but HIRHAM almost always simulates a situation of inversion and negative sensible heat flux; (2) during autumn and winter, observed near-surface stability is almost always that of inversions, consistent with HIRHAM simulations. This partially explains the small bias during autumn and winter

Review of China's scientific research progress in polar meteorology in the last 30 years

The Antarctic and Arctic are sensitive to global climate change; therefore, they are key regions of global climate change research. This paper, the progress in scientific investigations and research regarding the atmosphere in the polar regions over the last 30 years by Chinese scientists is summarized. Primary understanding of the relationship between the polar regions and global change, especially, the variations in time and space in the Antarctic and Arctic regions with respect to climate change is indicated. Operational weather forecasts for investigation of the polar regions have also been established. Moreover, changes in sea ice and their impact on the atmosphere of polar regions have been diagnosed and simulated. Parameterization of the atmospheric boundary layer of different underlying layers and changes in the atmospheric ozone in the polar region has also been experimented. Overall, there has been great progress in studies of the possible impact of changes in the atmospheric environment of polar regions on circulation in East Asia and the climate of China

Impacts of snow accumulation on air temperature measured by automatic weather stations on the Antarctic ice sheet

The heights of automatic weather station (AWS) sensors over the Antarctic ice sheet are nominal and change with snow accumulation or ablation. Therefore, the measured data may not be used directly. In this study, we analyzed the impact of snow accumulation on AWS observations using continuous measurements from three AWS that were deployed on the traverse route from the Zhongshan Station to Dome A over East Antarctica. We then corrected the measured air temperature to account for changes in the sensor height relative to the snow surface to improve the authenticity and representativeness of the observation data from the AWS. The results show that (i) the annual mean snow accumulations at Dome A, Eagle and LGB69 were approximately 0.11 m, 0.30 m and 0.49 m, respectively, and the corresponding annual mean air temperature differences between the corrected and measured values at 1 m in height were 0.34℃, 0.29℃ and 0.35℃; (ii) the impact on air temperature from accumulation decreases with height from the surface; (iii) the air temperature difference between the corrected and measured values was not directly proportional to the snow accumulation but was related to the seasonal air temperature variations and the intensity of the local surface inversion; and (iv) the averaged corrected air temperature was higher than the measured values except during the summer when there were days without temperature inversion. The magnitude of the temperature difference between the corrected and measured was mainly determined by snow accumulation and the intensity of the local surface inversion

Characteristics and spatial distribution of strong warming events in the central Arctic (2000–2019)

Arctic amplification in the context of global warming has received considerable attention, and mechanisms such as ice–albedo feedback and extratropical cyclone activity have been proposed to explain such abnormal warming. Since 2000, several short-term episodes of significant temperature rise have been observed in the Arctic; however, long-duration warming events in the central Arctic are less common and lack comprehensive research. Previous studies identified that amplified Rossby waves could connect Arctic warming with extreme weather events in mid-latitude regions, and thus the recent increase in the frequency of mid-latitude extreme weather is also a subject of intensive research. With consideration of temperature anomalies, this study defined a continuous warming process as a warming event and selected strong warming events based on duration. Analysis of National Centers for Environmental Prediction Reanalysis-2 surface air temperature data found that nine strong warming events occurred during 2000–2019, which could be categorized into three types based on the area of warming. This study also investigated the relation between strong warming events and sea ice concentration reduction, sudden stratospheric warming, and extratropical cyclone activities. After full consideration and comparison, we believe that strong warming events in the central Arctic are induced primarily by continuous transport of warm air from mid-latitude ocean areas

Antarctica Sea-Ice Oscillation and Its Possible Impact on Monsoon of South Sea

Antarctic sea-ice oscillation index with a seesaw pattern is defined using NCEP/NCAR reanalysis girds data of monthly Antarctica sea-ice concentration from 1979 to 2002. The relationships between the index of winter and the summer precipitations in China as well as the onset date of the summer East Asia monsoon are presented. The study result shows that the grids of correlation coefficients passed 5% confidence level between Antarctic sea-ice oscillation index and Antarctic sea-ice concentration are more than 1/3 of all grids of Antarctica sea-ice, that means the index can represent 1/3 sea-ice area. The winter index has a significant correlation with abnormal summer (June-August) precipitation in China. The area of positive correlation lies in the Yangtze River basin and its south, and that of negative correlation lies mainly in the north of Yangtze River basin. While the winter index is positive(negative), the onset date of South China Sea monsoon is earlier(later), with a probability of 79% (80%). Consequently, a conceptual modelis given in term of discussing the possible process between the winter Antarctic sea ice and the monsoon precipitation in China

Climate change: Impact on the Arctic, Antarctic and Tibetan Plateau

The Arctic, Antarctic and Tibetan Plateau are very sensitive to global climate change. Hence, it is urgent that we improve our understanding of how they respond to climate change, and how those responses in turn affect both regional and global climate. Against a background of current global warming, the three poles display climate diversities temporarily and spatially, which to different degrees affect the weather and climate over China. Enhanced monitoring of climate change in these three areas, as well as connected work on the responses and feedbacks of the three regions to climate change, will provide necessary support for adaptation and the sustainable development of the Chinese economy

Response of the East Asian climate system to water and heat changes of global frozen soil using NCAR CAM model

El siguiente trabajo tiene como objetivo analizar un corpus de obras poéticas publicadas en Chile durante la primera década del siglo XXI, a partir de las distintas simbolizaciones que ellas plantean en torno a dos figuras culturales que resultan claves para entender el imaginario de la letra poética actual en nuestro país. Nos referimos a la casa y el niño, ambas como metáforas de una habitabilidad fracasada e, incluso, imposible, que se produce como efecto de la economía neoliberal, consolidada en el campo cultural chileno tras el retorno a la democracia.The following article aims to analyze a corpus of poetic productions published in Chile during the first decade of the 21st century, starting from the different symbolizations they propose around two cultural figures, that are key to understand the imaginary of nowadays poetics. Those are, the home and the child, both as symbolizations of an unsuccessful habitability, even impossible, due to the effects that the neoliberal economy has created in the Chilean cultural space, after the return of democracy.El següent treball té com a objectiu analitzar un corpus d'obres poètiques publicades a Xile durant la primera dècada del segle XXI, a partir de les diferents simbolitzacions que aquestes plantegen entorn de dues figures culturals que resulten clau per entendre l'imaginari de la lletra poètica actual al nostre país. Ens referim a la casa i el nen, ambdues com a metàfores d'una habitabilitat fracassada i, fins i tot, impossible, que es produeix com a efecte de l'economia neoliberal, consolidada en el camp cultural xilè després del retorn a la democràcia

Structure and seasonal changes in atmospheric boundary layer on coast of the east Antarctic continent

The temperature, humidity, and vertical distribution of ozone in the Antarctic atmospheric boundary layer(ABL) and their seasonal changes are analyzed, by using the high-resolution profile data obtained during the International Polar Year 2008 to 2009 at Zhongshan Station, to further the understanding of the structure and processes of the ABL. The results show that the frequency of the convective boundary layer in the warm season accounts for 84% of its annual occurrence frequency. The frequency of the stable boundary layer in the cold season accounts for 71% of its annual occurrence frequency. A neutral boundary layer appears rarely. The average altitude of the convective boundary layer determined by the parcel method is 600 m; this is 200 to 300 m higher than that over inland Antarctica. The average altitude of the top of the boundary layer determined by the potential temperature gradient and humidity gradient is 1 200 m in the warm season and 1 500 m in the cold season. The vertical structures of ozone and specific humidity in the ABL exhibit obvious seasonal changes. The specific humidity is very high with greater vertical gradient in the warm season and very low with a lesser gradient in the cold season under 2 000 m. The atmospheric ozone in the ABL is consumed by photochemical processes in the warm season, which results in a slight difference in altitude. The sub-highest ozone center is located in the boundary layer, indicating that the ozone transferred from the stratosphere to the troposphere reaches the low boundary layer during October and November in Antarctica

Measurement and analysis of ozone, ultraviolet B and aerosol light scattering coefficients in the Arctic

Tropospheric ozone (O3), ultraviolet B (UVB) radiation and aerosol light scattering coefficients (SC) were investigated on a cruise ship during the fourth Chinese National Arctic Research Expedition from July 1 - September 20, 2010. The results showed that O3, UVB and SC decreased with increasing latitude, with minimum values recorded in the central Arctic Ocean. Average O3 concentrations were 15.9 ppbv and 15.1 ppbv in the Bering Sea and Arctic Ocean, respectively. Ozone concentrations increased to 17.5 ppbv in the high Arctic region. Average UVB values were 0.26 W * m(-2) and 0.14 W * m(-2) in the Bering Sea and Arctic Ocean, respectively. The average SC in the Bering Sea was 4.3 M * m(-1), more than twice the value measured in the Arctic Ocean, which had an average value of 1.7 M * m(-1). Overall, UVB and SC values were stable in the central Arctic Ocean

Temperature variations at the Great Wall and Zhongshan stations

Surface meteorological observations have been carried out at the Great Wall station (GW) and Zhongshan station (ZS) from 1984 to 2008 and from 1989 to 2008 respectively. The variation in mean air temperature and its trends are derived from the meteorological observation data recorded at both stations. The warming rate of the annual mean temperature at GW is similar to that at Bellingshausen station, which is about 3 km distant. Thus, the warming trend is representative of the King George Island region. The warming rate of ZS is less different from that at Davis station, which is about 100 km from ZS. It can be said that the meteorological data recorded at both stations are representative of the regions of the King George Island and east coast of the Antarctic