Analysis of air temperature in the lower troposphere with stratospheric circulation relationship

Abstract Atmospheric temperature and humidity profiles are important for weather prediction, but climate change has increased the interest in upper-air observations asking for very high-quality reference measurements. This paper discusses an experimental approach to determine the radiation-induced error on radiosonde air temperature measurements. On the one hand, solar shortwave and thermal longwave radiation profiles were accurately measured during radiosonde ascents from the surface to 35-km altitude. On the other hand, air temperature was measured with several thermocouples on the same flight, simultaneously under sun-shaded and unshaded conditions. The radiation experiments reveal that thermal radiation errors on the very thin thermocouple of the Meteolabor SRS-C34 radiosonde are similar during night- and daytime. They produce a radiative cooling in the lower troposphere and the upper stratosphere, but a radiative heating in the upper troposphere and lower stratosphere. Air temperature experiments with several thermocouples, however, show that solar radiation produces a radiative heating of about +0.2°C near the surface, which linearly increases to about +1°C at 32 km (~10 hPa). The new solar radiation error profile was then applied to SRS-C34 measurements made during the Eighth WMO Intercomparison of High Quality Radiosonde Systems, held in Yangjiang, China, in July 2010. The effects of thermal and solar radiation errors are finally shown in contrast to the 10 other internationally used radiosonde systems, which were flown during this international campaign.

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Comparisons of the Circulation Anomalies Associated with Extreme Heat in Different Regions of Eastern China

Journal of Climate ◽

10.1175/jcli-d-14-00818.1 ◽

2015 ◽

Vol 28 (14) ◽

pp. 5830-5844 ◽

Cited By ~ 32

Author(s):

Ruidan Chen ◽

Riyu Lu

Keyword(s):

Air Temperature ◽

North China ◽

Eastern China ◽

Lower Troposphere ◽

Circulation Pattern ◽

Extreme Heat ◽

Typical Pattern ◽

Upper Troposphere ◽

Anomalous Anticyclone ◽

The Many

Abstract The circulation associated with extreme heat (EH) typically shows an anomalous anticyclone that enhances temperature through adiabatic heating, but this study indicates obvious spatial variation in eastern China. The EH-related circulation pattern in eastern China can be classified into three categories: typical extratropical pattern, monsoonal pattern, and foehn pattern. EH over northeastern China and eastern north China is characterized by a typical pattern involving an anomalous anticyclone and subsidence, and the air temperature increases throughout almost the entire troposphere. In contrast, EH over the Yangtze River valley and south China is associated with the monsoonal pattern. Over these regions, the air temperature only increases in the lower troposphere as a result of anomalous subsidence and lower humidity that has resulted from a farther north transportation of water vapor by a stronger monsoonal southwesterly. Meanwhile, the air temperature decreases in the upper troposphere because of the decrease of latent heat caused by suppressed precipitation. On the other hand, western north China, with most of its stations located on the eastern leeside of mountains, is obviously influenced by the foehn effect on EH days. The foehn-related northwesterly anomalies bring drier and warmer air from the mountains to sink on the leeside and greatly increase the air temperature in the lower troposphere, particularly near the surface. Therefore, the impacts of monsoon and topography should be taken into consideration when EH-related circulations are discussed over the many regions of eastern China. As a result, the reliable projection of air temperature in these regions under global warming is a challenging problem.

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Regional climate simulation of present day temperature over India using RegCM3: Evaluation and analysis of model performance

MAUSAM ◽

10.54302/mausam.v68i4.716 ◽

2021 ◽

Vol 68 (4) ◽

pp. 607-620

Author(s):

R. K. S. MAURYA ◽

G. P. SINGH ◽

U. K. CHOUDHARY ◽

S. C. BHAN

Keyword(s):

Air Temperature ◽

Regional Climate ◽

Model Performance ◽

Lower Troposphere ◽

Mean Bias Error ◽

Western Himalayas ◽

Gangetic Plain ◽

North East ◽

Statistical Measures ◽

Atmospheric Level

The study has focused on the evaluation of model performance on simulated air temperature at surface and mid atmospheric level over the Indian subcontinent using a Regional Climate Model version 3 (RegCM3). The model is used at 40 km horizontal resolution over the domain approximately 58° E-102.5° E & 5° N-40° N for the period of 1982-2006. The temperatures at lower troposphere (850 hPa) and mid tropospheric level (500 hPa) have been simulated with reanalysis dataset of the National Centre for Environmental Prediction (NCEP). Various statistical measures namely Mean Bias Error (MBE), Root Mean Square Error (RMSE), Mean Percentage Error (MPE) and Correlation Coefficients (CCs) has been used to test the model results. It has been found that the RegCM3 is able to capture the main features of the observed mean surface climate and also patterns of surface and mid-level air temperatures over India. The model showed that cold biases were -4.29 °C (16.4%) at the lower troposphere, but insignificant at the mid atmospheric level in comparison to the NCEP dataset. The air temperature was well captured at mid tropospheric level. The CC between RegCM3 and NCEP is significantly high (0.82) over India in respect of annual surface air temperature (SAT). The trends of observed SAT were found to be significant increased by 0.32 °C with NCEP and 0.40 °C with RegCM3 over India. The annual SAT of cold biases ranging between -2 °C to -5 °C was found over major parts of India while cold biases of above -5 °C was found in the regions of low elevation or valley regions and below -2 °C in the mountainous regions. The analysis of annual and seasonal trends of maximum air temperature (Tmax), minimum air temperature (Tmin) and average air temperature (Tave) showed that the increasing trend was found over the Indo-Gangetic plain, Western Himalayas (WH) and North East India (NEI) in all seasons while decreasing trend over the North Central India (NCI) in the summer season and over the state of Gujarat in the monsoon season. The RegCM3 showed higher Water Vapour Mixing Ratio (WVMR) at the lower troposphere resulting more cooling at surface rather than at mid tropospheric level.

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Direct and semi-direct radiative forcing of biomass-burning aerosols over the southeast Atlantic (SEA) and its sensitivity to absorbing properties: a regional climate modeling study

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-13191-2020 ◽

2020 ◽

Vol 20 (21) ◽

pp. 13191-13216

Author(s):

Marc Mallet ◽

Fabien Solmon ◽

Pierre Nabat ◽

Nellie Elguindi ◽

Fabien Waquet ◽

...

Keyword(s):

Air Temperature ◽

Biomass Burning ◽

Radiative Forcing ◽

Climate Models ◽

Regional Climate ◽

Lower Troposphere ◽

Regional Climate Models ◽

Temperature Limit ◽

Radiative Heating ◽

Radiative Effects

Abstract. Simulations are performed for the period 2000–2015 by two different regional climate models, ALADIN and RegCM, to quantify the direct and semi-direct radiative effects of biomass-burning aerosols (BBAs) in the southeast Atlantic (SEA) region. Different simulations have been performed using strongly absorbing BBAs in accordance with recent in situ observations over the SEA. For the July–August–September (JAS) season, the single scattering albedo (SSA) and total aerosol optical depth (AOD) simulated by the ALADIN and RegCM models are consistent with the MACv2 climatology and MERRA-2 and CAMS-RA reanalyses near the biomass-burning emission sources. However, the above-cloud AOD is slightly underestimated compared to satellite (MODIS and POLDER) data during the transport over the SEA. The direct radiative effect exerted at the continental and oceanic surfaces by BBAs is significant in both models and the radiative effects at the top of the atmosphere indicate a remarkable regional contrast over SEA (in all-sky conditions), with a cooling (warming) north (south) of 10 ∘S, which is in agreement with the recent MACv2 climatology. In addition, the two models indicate that BBAs are responsible for an important shortwave radiative heating of ∼0.5–1 K per day over SEA during JAS with maxima between 2 and 4 km a.m.s.l. (above mean sea level). At these altitudes, BBAs increase air temperature by ∼0.2–0.5 K, with the highest values being co-located with low stratocumulus clouds. Vertical changes in air temperature limit the subsidence of air mass over SEA, creating a cyclonic anomaly. The opposite effect is simulated over the continent due to the increase in lower troposphere stability. The BBA semi-direct effect on the lower troposphere circulation is found to be consistent between the two models. Changes in the cloud fraction are moderate in response to the presence of smoke, and the models differ over the Gulf of Guinea. Finally, the results indicate an important sensitivity of the direct and semi-direct effects to the absorbing properties of BBAs. Over the stratocumulus (Sc) region, DRE varies from +0.94 W m−2 (scattering BBAs) to +3.93 W m−2 (most absorbing BBAs).

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Contrasting Relationship between Wintertime Blocking Highs over Europe–Siberia and Temperature Anomalies in the Yangtze River Basin

Monthly Weather Review ◽

10.1175/mwr-d-19-0152.1 ◽

2020 ◽

Vol 148 (7) ◽

pp. 2953-2970

Author(s):

Ning Shi ◽

SuolangTajie ◽

Pinyu Tian ◽

Yicheng Wang ◽

Xiaoqiong Wang

Keyword(s):

Air Temperature ◽

Yangtze River ◽

Yangtze River Basin ◽

Lower Troposphere ◽

The Tibetan Plateau ◽

The Yangtze River ◽

Local Cooling ◽

Reanalysis Dataset ◽

River Region ◽

Dipole Pattern

Abstract Based on the Japanese 55-year reanalysis dataset, this study identifies 92 Europe–Siberia blocking high events (ESBs) over the 60 winters (November–March) from 1958/59 to 2017/18. According to the influence on the surface air temperature at 2 m over the middle and lower reaches of the Yangtze River, the ESBs are classified into three types: cold, neutral, and warm. Although cold-type ESBs are dominant, the number of warm-type ESBs is not negligible. The present study mainly focuses on the differences between cold-type and warm-type ESBs. Both the cold-type ESBs and the warm-type ESBs are characterized by height anomalies with a northwest–southeast-tilting dipole pattern over the Eurasian continent in the mid- and upper troposphere. However, the tilting dipole pattern of the warm type is located to the northwest of its cold-type counterpart, which reflects differences in the propagation of Rossby wave packets. The Siberian high is stronger in cold-type ESBs than in warm-type ESBs. The induced advection of the climatological mean air temperature by the anomalous meridional wind velocity in the lower troposphere accounts for the largest portion of the observed tendency of the air temperature for both ESB types. In addition, diabatic heating tends to counteract the local cooling tendency of air temperature over the Yangtze River region for the cold-type ESBs. Finally, cold-type ESBs are generally characterized by air parcels originating in the region to the north and northeast of the Tibetan Plateau, while warm-type ESBs are characterized by diverse trajectories.

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Air temperature in the lower troposphere over Moscow during heat wave in summer of 2010

Оптика атмосферы и океана ◽

10.15372/aoo20151007 ◽

2015 ◽

Vol 28 (10) ◽

Keyword(s):

Heat Wave ◽

Air Temperature ◽

Lower Troposphere

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The Long-Term Trend of Upper-Air Temperature in China Derived from Microwave Sounding Data and Its Comparison with Radiosonde Observations

Journal of Climate ◽

10.1175/jcli-d-19-0742.1 ◽

2020 ◽

Vol 33 (18) ◽

pp. 7875-7895

Author(s):

Yanjun Guo ◽

Fuzhong Weng ◽

Guofu Wang ◽

Wenhui Xu

Keyword(s):

Air Temperature ◽

Decadal Variability ◽

Southern China ◽

Lower Troposphere ◽

Late Winter ◽

The Tibetan Plateau ◽

Term Trend ◽

Microwave Sounding ◽

Long Term Trend

AbstractCurrently, the satellite Microwave Sounding Unit (MSU/AMSU) datasets developed from three organizations—Remote Sensing Systems (RSS), the University of Alabama at Huntsville (UAH), and the NOAA Center for Satellite Applications and Research (STAR)—are often used to monitor the global long-term trends of temperatures in the lower troposphere (TLT), midtroposphere (TMT), total troposphere (TTT), troposphere and stratosphere (TTS), and lower stratosphere (TLS). However, the trend in these temperatures over China has not been quantitatively assessed. In this study, the decadal variability and long-term trend of upper-air temperature during 1979–2018 from three MSU datasets are first evaluated over China and compared with the proxy MSU dataset simulated from homogenized surface and radiosonde profiles (EQU) at 113 stations in China. The regional mean MSU trends over China during 1979–2018 are 0.22–0.27 (TLT), 0.15–0.22 (TMT), 0.20–0.27 (TTT), 0.02–0.14 (TTS), and from −0.33 to −0.36 (TLS) K decade−1, whereas the EQU trends are 0.31 (TLT), 0.19 (TMT), 0.24 (TTT), 0.07 (TTS), and −0.26 (TLS) K decade−1. The trends from RSS generally show a better agreement with those from EQU. The trends from both MSU and EQU exhibit seasonal and regional difference with a larger warming in TLT in February and March, and stronger cooling in TLS from late winter to spring. The TLT and TMT over the Tibetan Plateau and northwestern China show larger warming trends. The variability from MSU and EQU agree well except TLT in Tibet and southern China. The major difference in regional mean temperatures over China between MSU and EQU is related primarily to the satellite instrument changes during 1979–98 and the radiosonde system changes in China in the 2000s.

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Lower Tropospheric Temperatures 1978-2016: The Role Played By Anthropogenic Global Warming

Journal of Southern Hemisphere Earth System Science ◽

10.1071/es17002 ◽

2017 ◽

Vol 67 (1) ◽

pp. 2

Author(s):

G. P. Ayers

Keyword(s):

Air Temperature ◽

Temperature Increase ◽

Null Hypothesis ◽

Lower Troposphere ◽

Temperature Record ◽

Tropospheric Temperature ◽

System Variability ◽

Anthropogenic Contribution ◽

Different Sources ◽

Global Mean

The slowdown in tropospheric temperature increase between 1997-2016 led some commentators in Australia (and elsewhere) to repeat earlier assertions that there is an absence of any relationship between anthropogenic carbon dioxide increase and global air temperature. Here we test the null hypothesis that anthropogenic greenhouse forcing makes no contribution to global mean tropospheric temperature by analysing a satellite-derived lower tropospheric temperature record since 1978. A well-known heuristic model that separates variance in air temperature into components from different sources of climate variability is employed to determine what contribution anthropogenic greenhouse gases made to satellite-measured lower tropospheric temperature. Over the satellite record from December 1978 to the January 2016 the anthropogenic contribution to lower tropospheric temperature is estimated to be between +0.29 and +0.34K. Over the shorter segment of the record from December 1997 to January 2016 an anthropogenic contribution of +0.15K to the satellite-derived lower tropospheric air temperature was found. The slowdown in rate of temperature increase in that period is found simply to be a consequence of internal climate system variability that at other times has the opposite effect. The null hypothesis of no relationship between lower troposphere temperature and greenhouse gas increase is rejected.

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Air temperature in the lower troposphere over moscow during heat wave in the summer of 2010

Atmospheric and Oceanic Optics ◽

10.1134/s102485601603009x ◽

2016 ◽

Vol 29 (3) ◽

pp. 267-273 ◽

Cited By ~ 2

Author(s):

M. A. Lokoshchenko ◽

I. A. Korneva ◽

A. Z. Dubovetsky ◽

A. V. Kochin

Keyword(s):

Heat Wave ◽

Air Temperature ◽

Lower Troposphere

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