The pattern of radiative heating and cooling in the troposphere and lower stratosphere

1956 ◽  
Vol 236 (1205) ◽  
pp. 148-156 ◽  
Keyword(s):  
Cooling Rate ◽  
Water Vapour ◽  
Middle Atmosphere ◽  
Precipitable Water ◽  
Radiative Heating ◽  
The Arctic ◽  
Trade Wind ◽  
Water Vapour Content ◽  
Middle Latitudes ◽  
Heating And Cooling

For any meteorological effects of radiation, only those constituents of the air which have a very strong absorption in the infra-red are involved; these are water vapour and carbon dioxide. Several methods have been developed (Mügge & Möller 1932 a, b ; Elsasser 1942; Yamamoto 1952) for computing the radiation flux, and numerous calculations of these fluxes and of the cooling rates have been performed in the last 25 years (Ludwig 1935; Kortiim 1939; Thompson & Neiburger 1955). The results are summarized in figure 1, which shows the distribution of the tem­perature and of the cooling rate by water vapour in some characteristic atmospheres. The lower levels of the tropical atmosphere have a small cooling rate because the higher layers are very humid and the lower layers are thus sheltered from radiation losses. A contrary effect occurs at 30° latitude, where a very dry subsiding middle atmosphere is observed above a very wet trade-wind layer. In the arctic atmosphere a high cooling rate results for 1.5 km as a consequence of the conduction-like effect of radiation. The maximum values of the cooling rate are attained in the higher troposphere; they shift to somewhat lower levels with decreasing temperature and decreasing water-vapour content, from 10.5 km in the tropics to 7 km in middle latitudes and 4 km in the arctic. Apart from the extreme conditions in the arctic, the curves do not show much difference, and it is probable that all the differences may be understood by considering only the different amount of precipitable water.

scholarly journals A semiempirical error estimation technique for PWV derived from atmospheric radiosonde data

2016 ◽  
Vol 9 (9) ◽  
pp. 4759-4781 ◽  
Author(s):  
Julio A. Castro-Almazán ◽  
Gabriel Pérez-Jordán ◽  
Casiana Muñoz-Tuñón
Keyword(s):  
Water Vapour ◽  
Sampling Error ◽  
Precipitable Water ◽  
Semiempirical Method ◽  
The Arctic ◽  
Radiosonde Data ◽  
Optimum Number ◽  
Precipitable Water Vapour ◽  
Water Vapour Content ◽  
Covariance Components

Abstract. A semiempirical method for estimating the error and optimum number of sampled levels in precipitable water vapour (PWV) determinations from atmospheric radiosoundings is proposed. Two terms have been considered: the uncertainties in the measurements and the sampling error. Also, the uncertainty has been separated in the variance and covariance components. The sampling and covariance components have been modelled from an empirical dataset of 205 high-vertical-resolution radiosounding profiles, equipped with Vaisala RS80 and RS92 sondes at four different locations: Güímar (GUI) in Tenerife, at sea level, and the astronomical observatory at Roque de los Muchachos (ORM, 2300 m a.s.l.) on La Palma (both on the Canary Islands, Spain), Lindenberg (LIN) in continental Germany, and Ny-Ålesund (NYA) in the Svalbard Islands, within the Arctic Circle. The balloons at the ORM were launched during intensive and unique site-testing runs carried out in 1990 and 1995, while the data for the other sites were obtained from radiosounding stations operating for a period of 1 year (2013–2014). The PWV values ranged between ∼  0.9 and ∼  41 mm. The method sub-samples the profile for error minimization. The result is the minimum error and the optimum number of levels. The results obtained in the four sites studied showed that the ORM is the driest of the four locations and the one with the fastest vertical decay of PWV. The exponential autocorrelation pressure lags ranged from 175 hPa (ORM) to 500 hPa (LIN). The results show a coherent behaviour with no biases as a function of the profile. The final error is roughly proportional to PWV whereas the optimum number of levels (N0) is the reverse. The value of N0 is less than 400 for 77 % of the profiles and the absolute errors are always <  0.6 mm. The median relative error is 2.0 ±  0.7 % and the 90th percentile P90 = 4.6 %. Therefore, whereas a radiosounding samples at least N0 uniform vertical levels, depending on the water vapour content and distribution of the atmosphere, the error in the PWV estimate is likely to stay below ≈  3 %, even for dry conditions.

scholarly journals Water Vapour Assessment Using GNSS and Radiosondes over Polar Regions and Estimation of Climatological Trends from Long-Term Time Series Analysis

2021 ◽  
Vol 13 (23) ◽  
pp. 4871
Author(s):  
Monia Negusini ◽  
Boyan H. Petkov ◽  
Vincenza Tornatore ◽  
Stefano Barindelli ◽  
Leonardo Martelli ◽  
...  
Keyword(s):  
Water Vapour ◽  
Correlation Coefficients ◽  
Arctic Region ◽  
Precipitable Water ◽  
Satellite System ◽  
The Arctic ◽  
Polar Regions ◽  
Precipitable Water Vapour ◽  
Water Vapour Content

The atmospheric humidity in the Polar Regions is an important factor for the global budget of water vapour, which is a significant indicator of Earth’s climate state and evolution. The Global Navigation Satellite System (GNSS) can make a valuable contribution in the calculation of the amount of Precipitable Water Vapour (PW). The PW values retrieved from Global Positioning System (GPS), hereafter PWGPS, refer to 20-year observations acquired by more than 40 GNSS geodetic stations located in the polar regions. For GNSS stations co-located with radio-sounding stations (RS), which operate Vaisala radiosondes, we estimated the PW from RS observations (PWRS). The PW values from the ERA-Interim global atmospheric reanalysis were used for validation and comparison of the results for all the selected GPS and RS stations. The correlation coefficients between times series are very high: 0.96 for RS and GPS, 0.98 for RS and ERA in the Arctic; 0.89 for RS and GPS, 0.97 for RS and ERA in Antarctica. The Root-Mean-Square of the Error (RMSE) is 0.9 mm on average for both RS vs. GPS and RS vs. ERA in the Arctic, and 0.6 mm for RS vs. GPS and 0.4 mm for RS vs. ERA in Antarctica. After validation, long-term trends, both for Arctic and Antarctic regions, were estimated using Hector scientific software. Positive PWGPS trends dominate at Arctic sites near the borders of the Atlantic Ocean. Sites located at higher latitudes show no significant values (at 1σ level). Negative PWGPS trends were observed in the Arctic region of Greenland and North America. A similar behaviour was found in the Arctic for PWRS trends. The stations in the West Antarctic sector show a general positive PWGPS trend, while the sites on the coastal area of East Antarctica exhibit some significant negative PWGPS trends, but in most cases, no significant PWRS trends were found. The present work confirms that GPS is able to provide reliable estimates of water vapour content in Arctic and Antarctic regions too, where data are sparse and not easy to collect. These preliminary results can give a valid contribution to climate change studies.

scholarly journals Investigation of Arctic middle-atmospheric dynamics using 3 years of H<sub>2</sub>O and O<sub>3</sub> measurements from microwave radiometers at Ny-Ålesund

2019 ◽  
Author(s):  
Franziska Schranz ◽  
Brigitte Tschanz ◽  
Rolf Rüfenacht ◽  
Klemens Hocke ◽  
Mathias Palm ◽  
...  
Keyword(s):  
Water Vapour ◽  
Middle Atmosphere ◽  
Microwave Radiometer ◽  
Polar Vortex ◽  
The Arctic ◽  
High Time Resolution ◽  
Middle Atmospheric Dynamics ◽  
Wind Profiles ◽  
Microwave Radiometers

Abstract. We use 3 years of water vapour and ozone measurements to analyse dynamical events in the polar middle atmosphere such as sudden stratospheric warmings (SSW), polar vortex shifts, water vapour descent rates and periodicities. The measurements were performed with the two ground-based microwave radiometers MIAWARA-C and GROMOS-C which are co-located at the AWIPEV research base at Ny-Ålesund, Svalbard (79° N, 12° E) since September 2015. The almost continuous datasets of water vapour and ozone are characterised by a high time resolution in the order of hours. A thorough intercomparison of these datasets with models and measurements from satellite, ground-based and in-situ instruments was performed. In the upper stratosphere and lower mesosphere the MIAWARA-C profiles agree within 5 % with SD-WACCM simulations and ACE-FTS measurements whereas AuraMLS measurements show an average offset of 10–15 % depending on altitude but constant in time. Stratospheric GROMOS-C profiles are within 5 % of the satellite instruments AuraMLS and ACE-FTS and the ground-based microwave radiometer OZORAM which is also located at Ny-Ålesund. During these first three years of the measurement campaign typical phenomena of the Arctic middle atmosphere took place and we analysed their signatures in the water vapour and ozone datasets. Inside of the polar vortex in autumn we found the descent rate of mesospheric water vapour to be 435 m/day on average. In early 2017 distinct increases in mesospheric water vapour of about 2 ppm were observed when the polar vortex was displaced and midlatitude air was brought to Ny-Ålesund. Two major sudden stratospheric warmings took place in March 2016 and February 2018 where ozone enhancements of up to 4 ppm were observed. The zonal wind reversals accompanying a major SSW were captured in the GROMOS-C wind profiles which are retrieved from the ozone spectra. After the SSW in February 2018 the polar vortex re-established and the water vapour descent rate in the mesosphere was 355 m/day. In the water vapour and ozone time series signatures of atmospheric waves with periods close to 2, 5, 10 and 16 days were found.

scholarly journals Middle atmospheric water vapour and dynamics in the vicinity of the polar vortex during the Hygrosonde-2 campaign

2009 ◽  
Vol 9 (13) ◽  
pp. 4407-4417 ◽  
Author(s):  
S. Lossow ◽  
M. Khaplanov ◽  
J. Gumbel ◽  
J. Stegman ◽  
G. Witt ◽  
...  
Keyword(s):  
Water Vapour ◽  
Middle Atmosphere ◽  
Polar Vortex ◽  
The Arctic ◽  
Small Scale ◽  
Air Masses ◽  
Mixing Ratios ◽  
Water Vapour Concentration ◽  
Wind Shears

Abstract. The Hygrosonde-2 campaign took place on 16 December 2001 at Esrange/Sweden (68° N, 21° E) with the aim to investigate the small scale distribution of water vapour in the middle atmosphere in the vicinity of the Arctic polar vortex. In situ balloon and rocket-borne measurements of water vapour were performed by means of OH fluorescence hygrometry. The combined measurements yielded a high resolution water vapour profile up to an altitude of 75 km. Using the characteristic of water vapour being a dynamical tracer it was possible to directly relate the water vapour data to the location of the polar vortex edge, which separates air masses of different character inside and outside the polar vortex. The measurements probed extra-vortex air in the altitude range between 45 km and 60 km and vortex air elsewhere. Transitions between vortex and extra-vortex usually coincided with wind shears caused by gravity waves which advect air masses with different water vapour volume mixing ratios. From the combination of the results from the Hygrosonde-2 campaign and the first flight of the optical hygrometer in 1994 (Hygrosonde-1) a clear picture of the characteristic water vapour distribution inside and outside the polar vortex can be drawn. Systematic differences in the water vapour concentration between the inside and outside of the polar vortex can be observed all the way up into the mesosphere. It is also evident that in situ measurements with high spatial resolution are needed to fully account for the small-scale exchange processes in the polar winter middle atmosphere.

Precipitable water vapour content above the Roque de los Muchachos Observatory from GPS estimations

2009 ◽  
Author(s):  
B. García-Lorenzo ◽  
J. A. Castro-Almazán ◽  
A. Eff-Darwich ◽  
C. Muñoz-Tuñón ◽  
N. Pinilla-Alonso ◽  
...  
Keyword(s):  
Water Vapour ◽  
Precipitable Water ◽  
Precipitable Water Vapour ◽  
Water Vapour Content

scholarly journals Mesopause dynamics from the scandinavian triangle of radars within the PSMOS-DATAR Project

2004 ◽  
Vol 22 (2) ◽  
pp. 367-386 ◽  
Author(s):  
A. H. Manson ◽  
C. E. Meek ◽  
C. M. Hall ◽  
S. Nozawa ◽  
N. J. Mitchell ◽  
...  
Keyword(s):  
Large Scale ◽  
Middle Atmosphere ◽  
The Arctic ◽  
Small Scale ◽  
Wind Variability ◽  
Middle Latitudes ◽  
Radar Systems ◽  
Waves And Tides ◽  
Year 2000 ◽  
Mf Radar

Abstract. The "Scandinavian Triangle" is a unique trio of radars within the DATAR Project (Dynamics and Temperatures from the Arctic MLT (60–97km) region): Andenes MF radar (69°N, 16°E); Tromsø MF radar (70°N, 19°E) and Esrange "Meteor" radar (68°N, 21°E). The radar-spacings range from 125-270km, making it unique for studies of wind variability associated with small-scale waves, comparisons of large-scale waves measured over small spacings, and for comparisons of winds from different radar systems. As such it complements results from arrays having spacings of 25km and 500km that have been located near Saskatoon. Correlation analysis is used to demonstrate a speed bias (MF smaller than the Meteor) between the radar types, which varies with season and altitude. Annual climatologies for the year 2000 of mean winds, solar tides, planetary and gravity waves are presented, and show indications of significant spatial variability across the Triangle and of differences in wave characteristics from middle latitudes. Key words: Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides: instrument and techniques)

scholarly journals Observations of surface radiation and stratospheric processes at Thule Air Base, Greenland, during the IPY

2014 ◽  
Vol 57 (3) ◽  
Author(s):  
Giovanni Muscari ◽  
Claudia Di Biagio ◽  
Alcide di Sarra ◽  
Marco Cacciani ◽  
Svend Erik Ascanius ◽  
...  
Keyword(s):  
Water Vapour ◽  
Surface Albedo ◽  
Middle Atmosphere ◽  
Stratospheric Ozone ◽  
Surface Radiation ◽  
Atmospheric Composition ◽  
Radiation Budget ◽  
The Arctic ◽  
Western Coast ◽  
International Polar Year

<p>Ground-based measurements of atmospheric parameters have been carried out for more than 20 years at the Network for the Detection of Atmospheric Composition Change (NDACC) station at Thule Air Base (76.5°N, 68.8°W), on the north-western coast of Greenland. Various instruments dedicated to the study of the lower and middle polar atmosphere are installed at Thule in the framework of a long standing collaboration among Danish, Italian, and US research institutes and universities. This effort aims at monitoring the composition, structure and dynamics of the polar stratosphere, and at studying the Arctic energy budget and the role played by different factors, such as aerosols, water vapour, and surface albedo. During the International Polar Year (IPY), in winter 2008-2009, an intensive measurement campaign was conducted at Thule within the framework of the IPY project “Ozone layer and UV radiation in a changing climate evaluated during IPY” (ORACLE-O3) which sought to improve our understanding of the complex mechanisms that lead to the Arctic stratospheric O<span><sub>3</sub></span> depletion. The campaign involved a lidar system, measuring aerosol backscatter and depolarization ratios up to 35 km and atmospheric temperature profiles from 25 to 70 km altitude, a ground-based millimeter-wave spectrometer (GBMS) used to derive stratospheric mixing ratio profiles of different chemical species involved in the stratospheric ozone depletion cycle, and then ground-based radiometers and a Cimel sunphotometer to study the Arctic radiative budget at the surface. The observations show that the surface radiation budget is mainly regulated by the longwave component throughout most of the year. Clouds have a significant impact contributing to enhance the role of longwave radiation. Besides clouds, water vapour seasonal changes produce the largest modification in the shortwave component at the surface, followed by changes in surface albedo and in aerosol amounts. For what concerns the middle atmosphere, during the first part of winter 2008-2009 the cold polar vortex allowed for the formation of polar stratospheric clouds (PSCs) which were observed above Thule by means of the lidar. This period was also characterized by GBMS measurements of low values of O<span><sub>3</sub></span> due to the catalytic reactions prompted by the PSCs. In mid-January, as the most intense Sudden Stratospheric Warming event ever observed in the Arctic occurred, GBMS and lidar measurements of O<span><sub>3</sub></span>, N<span><sub>2</sub></span>O, CO and temperature described its evolution as it propagated from the upper atmosphere to the lower stratosphere.</p>

Diurnal cycle of GNSS-derived precipitable water vapour in tropical regions

2020 ◽  
Author(s):  
Zofia Bałdysz ◽  
Grzegorz Nykiel ◽  
Dariusz Baranowski ◽  
Beata Latos ◽  
Mariusz Figurski
Keyword(s):  
Water Vapour ◽  
Diurnal Cycle ◽  
Asian Summer Monsoon ◽  
Precipitable Water ◽  
Tropical Atmosphere ◽  
International Gnss Service ◽  
Precipitable Water Vapour ◽  
Water Vapour Content ◽  
Inter Tropical Convergence Zone ◽  
Tropical Regions

&lt;p&gt;Convective processes in the tropical atmosphere and their diurnal cycles have important repercussions for the circulations in the tropical regions and beyond. Monitoring of the water vapour content in the tropical atmosphere remains a challenge due to its high temporal and spatial variability. Global models tend to fail to correctly capture the diurnal convection, limiting forecasting accuracy. In this work, we investigated precipitable water vapour (PWV) diurnal cycle, precipitation and infrared &amp;#160;brightness temperature (TB) data over the tropical area. We used in-situ observations from 44 IGS (International GNSS Service) stations covering time span of 18 years, together with satellite-based precipitation and cloudiness data, taken from the Tropical Rainfall Measurement Mission gridded dataset (TRMM 3B42 v7) and the global, merged infrared (IR) dataset, respectively. The data provided an opportunity to examine the characteristics of a diurnal cycle of PWV, precipitation and TB over the study area in greater detail than before.&lt;/p&gt;&lt;p&gt;In particular, our results show that the diurnal cycle of PWV and TB were almost entirely dominated by mono-modal distributions. The diurnal cycle of precipitation onshore (continental areas or big islands; continental regime) had a single late afternoon peak, and that offshore (small islands; oceanic regime) had both a midday and a nocturnal peak. Daily amplitude phase shift of PWV and precipitation at onshore stations with a continental regime consistently occurred at the same time, while TB maximum peaked about five hours later. Furthermore, results show that the daily mean and the amplitude of the diurnal cycle of PWV, precipitation and TB appeared smaller on offshore stations, exhibited to an oceanic regime, than on onshore, continental stations. Additional analysis of seasonal variations of GNSS-derived PWV shows the usefulness of such measurements for tracking propagation of longer-scale phenomena, such as Inter Tropical Convergence Zone (ITCZ), Southeast Asian monsoon or East Asian summer monsoon.&lt;/p&gt;

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