scholarly journals STUDY OF THE WATER VAPOR CONCENTRATION IN THE ATMOSPHERIC BOUNDARY LAYER 2 OVER THE BRAZIL-MALVINAS CONFLUENCE REGION

2020 ◽  
Vol 38 (1) ◽  
Author(s):  
Rose Ane Pereira de Freitas
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Atmospheric Boundary Layer ◽  
Observational Data ◽  
Specific Humidity ◽  
Radiosonde Data ◽  
Vapor Concentration ◽  
Free Atmosphere ◽  
Atmospheric Infrared Sounder ◽  
Southwestern Atlantic Ocean

ABSTRACT. The concentration of water vapor on the marine atmospheric boundary layer (MABL) at the Brazil-Malvinas Confluence (BMC) region in the Southwestern Atlantic Ocean was analyzed from 130 radiosondes collected during 10 oceanographic cruises carried out during the months of October or November from 2004 to 2015. During the same period, specific humidity and air temperature data from reanalysis (CFSR/CFSv2) and from the Atmospheric Infrared Sounder (AIRS) onboard the Aqua satellite were also used. The results of show that the thermal gradients between the warm waters of the Brazil Current (BC) and the cold waters of the Malvinas Current (MC) in BMC region are capable to produce significant differences on the MABL's water vapor content on both sides of the oceanographic front. On the average over the warmer waters of the BC the MABL is more humid. However, transient atmospheric systems, can mitigate or intensify the concentration of water vapor inside the MABL. The comparison between in situ radiosonde data and AIRS and CFSR profiles revealed that, in general, the CFSR/ CFSv2 data presented a better agreement with observational data in both sides of the BMC. The AIRS data satisfactorily represent the observational data in conditions of a cloud-free atmosphere. ESTUDO DA CONCENTRAÇÃO DE VAPOR D’ÁGUA NA CAMADA LIMITE ATMOSFÉRICA SOBRE A REGIÃO DA CONFLUÊNCIA BRASIL-MALVINAS RESUMO. A concentração de vapor d’água na camada limite atmosférica marítima (CLAM) na região da Confluência BrasilMalvinas (CBM) no Oceano Atlântico Sudoeste foi analisada a partir de 130 radiossondas coletadas durante 10 cruzeiros oceanográficos realizados nos meses de outubro ou novembro de 2004 até 2015. Durante o mesmo período, também foram utilizados dados de umidade específica e temperatura do ar provenientes da reanálise (CFSR/CFSv2) e do Atmospheric Infrared Sounder (AIRS) a bordo do satélite Aqua. Os resultados mostram que os gradientes térmicos entre as águas quentes da Corrente do Brasil (CB) e as águas frias da Corrente de Malvinas (CM) na região do CBM são capazes de produzir diferenças significativas no conteúdo de vapor de água da CLAM em ambos os lados da frente oceanográfica. Em média, sobre as águas mais quentes do CB, o CLAM é mais úmido. Entretanto, sistemas atmosféricos transientes podem mitigar ou intensificar a concentração de vapor de água dentro do CLAM. A comparações entre os dados mostraram que, em geral, os dados do CFSR/ CFSv2 apresentaram melhor concordância com os dados observacionais em ambos os lados da CBM. Os dados do AIRS representam satisfatoriamente os dados observacionais em condições atmosféricas livre de nuvens.

scholarly journals Relação entre o Vapor D’Água Atmosférico e a Temperatura da Superfície do Mar Sobre a Região da Confluência Brasil-Malvinas, com Base em Dados Coletados In Situ (Relationship between Atmospheric Water Vapor Content and the Sea Surface Temperature in the Brazil-Malvinas Confluence considering Data Collected In Situ)

2019 ◽  
Vol 12 (5) ◽  
pp. 1687
Author(s):  
Rose Ane Pereira De Freitas ◽  
Ronald Buss Souza ◽  
Rafael Reis ◽  
Douglas Lindemann
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Surface Temperature ◽  
Atmospheric Boundary Layer ◽  
Sea Surface Temperature ◽  
Water Vapor Content ◽  
Sea Surface ◽  
Specific Humidity ◽  
Vapor Concentration

A atmosfera consiste em um dos menores reservatórios de água do planeta, contribuindo com 0,001% da massa total da água presente, porém, sendo de fundamental importância para os processos físicos na atmosfera. A partir de dados obtidos através de 130 perfis de radiossondas realizados durante dez cruzeiros oceanográficos nos meses de outubro e novembro, entre 2004 e 2015, analisa-se a influência dos gradientes de temperatura da superfície do mar (TSM) e a passagem de sistemas atmosféricos transientes na variabilidade espaço-temporal da concentração de vapor d’água da camada limite atmosférica marinha (CLAM), sobre a região da Confluência Brasil Malvinas (CBM), enfatizando-se a Operação Antártica 31 (OP31). Os dados de vapor d’água são obtidos calculando-se umidade específica em superfície e água precipitável dentro da camada limite atmosférica. Os resultados mostram que os gradientes térmicos entre as águas quentes da Corrente do Brasil (CB) e as águas frias da Corrente das Malvinas (CM) produzem diferenças significativas no conteúdo de vapor d'água da CLAM nos dois lados da frente oceanográfica. Na superfície, o valor médio da umidade específica sobre o lado quente (frio) foi 8,4 ± 1,67 mm (7,08 ± 1,51 mm). A CLAM foi localmente modulada pela TSM, sendo cerca de 2g/kg mais úmida sobre a região quente da frente oceanográfica em relação à região fria. Em todas as observações realizadas, o vapor d’água integrado na CLAM foi diretamente influenciada pela passagem de sistemas atmosféricos transiente.    A B S T R A C TThe atmosphere is the smallest contributor of the planet's water tanks, providing only 0.001% of the water total mass, however, it is of fundamental importance for playing a key role in the atmosphere's physical processes. The data were obtained from 130 radiosondes profiles taken during ten oceanographic cruises carried out during the months of October and November between 2004 and 2015, analyzed the influence of the sea surface temperature (SST) gradients and the passage of transient atmospheric systems at the spatial-temporal variability of the water vapor concentration within the marine atmospheric boundary layer (MABL), over Brazil-Malvinas Confluence (BMC), emphasizing the Antarctic Operation 31 (AO31). Water vapor data are obtained by calculating surface specific moisture and precipitable water within the atmospheric boundary layer. The results show that the thermal gradients between the warm waters of Brazil Current and the cold waters of the Malvinas Current were able to produce significant differences in the water vapor content of the MABL on both sides of the oceanographic front. On the surface, the average of the specific humidity over the warm (cold) side was 8.4 ± 1.67 mm (7.08 ± 1.51 mm). The MABL was locally modulated by the SST, being about 2 g/kg wetter over the warm part of the front with respect to the cold one. In all the observations made, the water vapor integrated in the MABL was directly influenced by the passage of transient atmospheric systems.Key words: Southwest Atlantic; Oceanographic front; Transient atmospheric system

scholarly journals Relação entre o Vapor D’Água Atmosférico e a Temperatura da Superfície do Mar Sobre a Região da Confluência Brasil-Malvinas, com Base em Dados Coletados In Situ (Relationship between Atmospheric Water Vapor Content and the Sea Surface Temperature in the Brazil-Malvinas Confluence considering Data Collected In Situ)

2019 ◽  
Vol 12 (4) ◽  
pp. 1370
Author(s):  
Rose Ane Pereira de Freitas ◽  
Ronald Buss de Souza ◽  
Rafael Afonso do Nascimento Reis
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Atmospheric Boundary Layer ◽  
Water Vapor Content ◽  
Specific Humidity ◽  
Vapor Concentration ◽  
Spatial And Temporal Variability ◽  
Southwest Atlantic ◽  
Atmospheric Systems

O objetivo deste trabalho foi analisar a influência dos gradientes de TSM e da passagem de sistemas atmosféricos transientes sobre a região da Confluência Brasil-Malvinas (CBM) no Oceano Atlântico Sudoeste e descrever a variabilidade espacial e temporal da concentração de vapor d’água dentro da camada limite atmosférica marinha (CLAM). Os dados foram obtidos a partir de 130 perfis de radiossondas realizados durante dez cruzeiros oceanográficos feitos durante os meses de outubro e novembro entre 2004 e 2015. Os resultados mostram que os gradientes termais entre as águas quentes da Corrente do Brasil e as águas frias da Corrente das Malvinas foram capazes de produzir diferenças significativas no conteúdo de vapor d'água na CLAM nos dois lados da frente oceanográfica. Na superfície, o valor médio da umidade específica sobre o lado quente (frio) foi 8,4 ± 1,67 mm (7,08 ± 1,51 mm). Em todas as observações realizadas, a umidade integrada na CLAM foi diretamente influenciada pela advecção e pela passagem de sistemas atmosféricos transientes.  A B S T R A C TThe objective of this work was to analyze the influence of the SST gradients and the passage of transient atmospheric systems at the Brazil-Malvinas Confluence (BMC) region in the Southwest Atlantic Ocean, and to describe the spatial and temporal variability of the water vapor concentration within the marine atmospheric boundary layer (MABL). The data were obtained from 130 radiosondes profiles taken during ten oceanographic cruises carried out during the months of October and November between 2004 and 2015. The results show that the thermal gradients between the warm waters of Brazil Current and the cold waters of the Malvinas Current were able to produce significant differences in the water vapor content of the MABL on both sides of the oceanographic front. On the surface, the average of the specific humidity over the warm (cold) side was 8.4 ± 1.67 mm (7.08 ± 1.51 mm). In all the observations made, the water vapor integrated in the MABL was directly influenced by the advection and by the passage of transient atmospheric systems. Key words: Water Vapor; Brazil-Malvinas Confluence; Atmospheric boundary layer

scholarly journals Diurnal Variation of Water Vapor Mixing between the Atmospheric Boundary Layer and Free Atmosphere over Changwu, the Loess Plateau in China

SOLA ◽  
2008 ◽  
Vol 4 ◽  
pp. 33-36 ◽  
Author(s):  
Atsuhiro Takahashi ◽  
Tetsuya Hiyama ◽  
Masanori Nishikawa ◽  
Hatsuki Fujinami ◽  
Atsushi Higuchi ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Atmospheric Boundary Layer ◽  
Diurnal Variation ◽  
Loess Plateau ◽  
The Loess Plateau ◽  
Free Atmosphere

scholarly journals Soil Moisture-Boundary Layer Feedbacks on the Loess Plateau in China Using Radiosonde Data with 1-D Atmospheric Boundary Layer Model

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1619
Author(s):  
Yingsai Ma ◽  
Xianhong Meng ◽  
Yinhuan Ao ◽  
Ye Yu ◽  
Guangwei Li ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Soil Moisture ◽  
Atmospheric Boundary Layer ◽  
Loess Plateau ◽  
Atmospheric Stability ◽  
Heat Fluxes ◽  
Radiosonde Data ◽  
Atmospheric Conditions ◽  
The Loess Plateau ◽  
The Impact

The Loess Plateau is one land-atmosphere coupling hotspot. Soil moisture has an influence on atmospheric boundary layer development under specific early-morning atmospheric thermodynamic structures. This paper investigates the sensitivity of atmospheric convection to soil moisture conditions over the Loess Plateau in China by using the convective triggering potential (CTP)—humidity index (HIlow) framework. The CTP indicates atmospheric stability and the HIlow indicates atmospheric humidity in the low-level atmosphere. By comparing the model outcomes with the observations, the one-dimensional model achieves realistic daily behavior of the radiation and surface heat fluxes and the mixed layer properties with appropriate modifications. New CTP-HIlow thresholds for soil moisture-atmosphere feedbacks are found in the Loess Plateau area. By applying the new thresholds with long-time scales sounding data, we conclude that negative feedback is dominant in the north and west portion of the Loess Plateau; positive feedback is predominant in the south and east portion. In general, this framework has predictive significance for the impact of soil moisture on precipitation. By using this new CTP-HIlow framework, we can determine under what atmospheric conditions soil moisture can affect the triggering of precipitation and under what atmospheric conditions soil moisture has no influence on the triggering of precipitation.

Airborne water vapor DIAL estimation of humidity fluxes and atmospheric boundary-layer parameters

1997 ◽  
Author(s):  
Christoph Kiemle ◽  
Gerhard Ehret ◽  
K. J. Davis ◽  
Donald H. Lenschow
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Atmospheric Boundary Layer

scholarly journals Assessment of COSMIC radio occultation retrieval product using global radiosonde data

2012 ◽  
Vol 5 (6) ◽  
pp. 8405-8434
Author(s):  
B.-R. Wang ◽  
X.-Y. Liu ◽  
J.-K. Wang
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Relative Error ◽  
Radio Occultation ◽  
Water Vapor Pressure ◽  
Specific Humidity ◽  
Radiosonde Data ◽  
Cosmic Radio ◽  
Horizontal Distance ◽  
Matching Criteria

Abstract. The radio occultation retrieval product of the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation sounding system was verified using the global radiosonde from 2007 to 2010. 4 yr of samples were used to collect quantities of data using much stricter matching criteria than previous studies to obtain more accurate results. The horizontal distance between the radiosonde station and the occultation event is within 100 km, and the time window is 1 h. The comparison was performed from 925 hPa to 10 hPa. The results indicated that the COSMIC's temperature data agreed well with the radiosonde data. The global mean temperature bias was −0.09 K, with a standard deviation (SD) of 1.72 K. The water vapor pressure of COSMIC showed a systematic bias in relation to radiosonde in higher layers. The mean specific humidity bias of 925–200 hPa is about −0.011 g kg−1, with a SD of about 0.662 g kg−1. The COSMIC quality control process could not detect some abnormal extremely small humidity data which occured frequently in subtropical zone. Despite the large relative error of water vapor pressure, the relative error of refractivity is small. This paper also provides a comparison of eight radiosonde types with COSMIC product. Because the retrieval product is affected by the background error which differed between different regions, the COSMIC retrieval product could be used as a benchmark if the precision requirement is not strict.

Penman and Priestley-Taylor approaches in Atmospheric Boundary-Layer Dynamics

2020 ◽  
Author(s):  
Jun Yin ◽  
Amilcare Porporato
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Surface Temperature ◽  
Atmospheric Boundary Layer ◽  
Slab Model ◽  
Unified Framework ◽  
Surface Evaporation ◽  
Analytical Approximations ◽  
Taylor Approximation ◽  
Boundary Layer Dynamics

<p>By linearizing the saturation water vapor curve, Penman (1948) not only found the famous explicit approximation of wet-surface evaporation but also obtained a less well-known expression of surface temperature. Here the latter has been taken into the slab model of Atmospheric Boundary Layer (ABL) to derive multiple analytical approximations of ABL dynamics, which share the features of the Penman equation with evaporation driven by energy and drying power of the air. Noticing that these two parts of evaporation are proportional to each other within the Priestley-Taylor approximation at sub-daily timescale, a unified framework is obtained that links the Penman approach and Priestley-Taylor method to the diurnal behaviors of ABL. The resulting model is useful for diagnosing the land-atmosphere interactions.</p>

scholarly journals Assessment of COSMIC radio occultation retrieval product using global radiosonde data

2013 ◽  
Vol 6 (4) ◽  
pp. 1073-1083 ◽  
Author(s):  
B.-R. Wang ◽  
X.-Y. Liu ◽  
J.-K. Wang
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Relative Error ◽  
Radio Occultation ◽  
Water Vapor Pressure ◽  
Specific Humidity ◽  
Radiosonde Data ◽  
Cosmic Radio ◽  
The Mean ◽  
Matching Criteria

Abstract. The radio occultation retrieval product of the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Radio Occultation sounding system was verified using the global radiosonde data from 2007 to 2010. Samples of 4 yr were used to collect quantities of data using much stricter matching criteria than previous studies to obtain more accurate results. The horizontal distance between the radiosonde station and the occultation event is within 100 km, and the time window is 1 h. The comparison was performed from 925 hPa to 10 hPa. The results indicated that the COSMIC's temperature data agreed well with the radiosonde data. The global mean temperature bias was −0.09 K, with a standard deviation (SD) of 1.72 K. According to the data filtration used in this paper, the mean specific humidity bias of 925–200 hPa is −0.012 g kg−1, with a SD of 0.666 g kg−1, and the mean relative error of water vapor pressure is about 33.3%, with a SD of 107.5%. The COSMIC quality control process failed to detect some of the abnormal extremely small humidity data which occurred frequently in subtropical zone. Despite the large relative error of water vapor pressure, the relative error of refractivity is small. This paper also provides a comparison of eight radiosonde types with COSMIC product. Because the retrieval product is affected by the background error which differed between different regions, the COSMIC retrieval product could be used as a benchmark if the precision requirement is not strict.

scholarly journals Temperature profiling of the atmospheric boundary layer with rotational Raman lidar during the HD(CP)<sup>2</sup> Observational Prototype Experiment

2015 ◽  
Vol 15 (5) ◽  
pp. 2867-2881 ◽  
Author(s):  
E. Hammann ◽  
A. Behrendt ◽  
F. Le Mounier ◽  
V. Wulfmeyer
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Temperature Gradient ◽  
Atmospheric Boundary Layer ◽  
Average Power ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Backscatter Signal ◽  
Low Background ◽  
Water Vapor Mixing Ratio

Abstract. The temperature measurements of the rotational Raman lidar of the University of Hohenheim (UHOH RRL) during the High Definition of Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observation Prototype Experiment (HOPE) in April and May 2013 are discussed. The lidar consists of a frequency-tripled Nd:YAG laser at 355 nm with 10 W average power at 50 Hz, a two-mirror scanner, a 40 cm receiving telescope, and a highly efficient polychromator with cascading interference filters for separating four signals: the elastic backscatter signal, two rotational Raman signals with different temperature dependence, and the vibrational Raman signal of water vapor. The main measurement variable of the UHOH RRL is temperature. For the HOPE campaign, the lidar receiver was optimized for high and low background levels, with a novel switch for the passband of the second rotational Raman channel. The instrument delivers atmospheric profiles of water vapor mixing ratio as well as particle backscatter coefficient and particle extinction coefficient as further products. As examples for the measurement performance, measurements of the temperature gradient and water vapor mixing ratio revealing the development of the atmospheric boundary layer within 25 h are presented. As expected from simulations, a reduction of the measurement uncertainty of 70% during nighttime was achieved with the new low-background setting. A two-mirror scanner allows for measurements in different directions. When pointing the scanner to low elevation, measurements close to the ground become possible which are otherwise impossible due to the non-total overlap of laser beam and receiving telescope field of view in the near range. An example of a low-level temperature measurement is presented which resolves the temperature gradient at the top of the stable nighttime boundary layer 100 m above the ground.

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