Water vapor density profile statistics in the atmospheric boundary layer

Ground-based 12-channel microwave radiometer profiler TP/WVP-3000 can provide temperature and vapor density profile per minute up to 10 km height. The observations feature apparent change before heavy rainfall obtained by TP/WVP-3000 is presented in this paper. It demonstrates the detailed thermodynamic features that the atmosphere becomes colder and drier above height 3-4 km about 9 hours before the rain, the integrated water vapor gradually increases from 5 cm to 9 cm, the integrated cloud water change from near zero to 15 mm and the vapor density also increases rapidly about half an hour before the rain, which can be concluded that the radiometer profiler is able to improve the understanding of mesoscale weather in this case due to the profiler significantly improves the temporal resolution of atmospheric thermodynamic observations.

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

10.5194/egusphere-egu2020-9216 ◽

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>

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-2867-2015 ◽

2015 ◽

Vol 15 (5) ◽

pp. 2867-2881 ◽

Cited By ~ 44

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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3D Water Vapor Field in the Atmospheric Boundary Layer Observed with Scanning Differential Absorption Lidar

10.5194/amt-2015-393 ◽

2016 ◽

Cited By ~ 1

Author(s):

F. Späth ◽

A. Behrendt ◽

S. K. Muppa ◽

S. Metzendorf ◽

A. Riede ◽

...

Keyword(s):

Boundary Layer ◽

Water Vapor ◽

Atmospheric Boundary Layer ◽

Elevation Angle ◽

Three Dimensions ◽

Dimensional Structure ◽

Differential Absorption ◽

Differential Absorption Lidar ◽

3 Dimensional ◽

Western Germany

Abstract. The scanning differential absorption lidar (DIAL) of the University of Hohenheim (UHOH) determines fields of the atmospheric water vapor number density with a temporal resolution of a few seconds and spatial resolution of up to a few tens of meters. We present three case studies which show that this high resolution combined with 2- and 3-dimensional scans allows for new insights in the 3-dimensional structure of the water vapor field in the atmospheric boundary layer (ABL). In spring 2013, the UHOH DIAL was operated within the scope of the HD(CP)2 Observational Prototype Experiment (HOPE) in western Germany. HOPE was part of the project High Definition of Clouds and Precipitation for advancing Climate Prediction (HD(CP)2). Range-height indicator (RHI) scans of the UHOH DIAL show the water vapor heterogeneity within a range of a few kilometers and its impact on the formation of clouds at the ABL top. The uncertainty of the measured data was assessed by extending a technique, which was formerly applied to vertical time series, to scanning data. Typically, even during daytime, the accuracy of the DIAL measurements is between 0.5 and 0.8 g m−3 (or < 6 %) within the ABL, so that now the performance of an RHI scan from the surface to an elevation angle of 90 degrees becomes possible within 10 min. In summer 2014, the UHOH DIAL participated in the Surface-Atmosphere-Boundary-Layer-Exchange (SABLE) campaign in south-western Germany. Volume scans show the water vapor field in three dimensions. In this case, multiple humidity layers were present. Differences in their heights in different directions can be attributed to different surface elevation. With low elevation scans in the surface layer, the humidity profiles and gradients related to different land use and surface stabilities were also revealed.

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A Raman Lidar with a Deep Ultraviolet Laser for Continuous Water Vapor Profiling in the Atmospheric Boundary Layer

EPJ Web of Conferences ◽

10.1051/epjconf/202023703001 ◽

2020 ◽

Vol 237 ◽

pp. 03001

Author(s):

Masanori Yabuki ◽

Yuya Kawano ◽

Yusaku Tottori ◽

Makoto Tsukamoto ◽

Eiji Takeuchi ◽

...

Keyword(s):

Boundary Layer ◽

Water Vapor ◽

Atmospheric Boundary Layer ◽

Environmental Conditions ◽

Raman Lidar ◽

Backscatter Signal ◽

Ultraviolet Laser ◽

Deep Ultraviolet ◽

Temperature Controlled

A Raman lidar with a deep ultraviolet laser was constructed to continuously monitor water vapor distributions in the atmospheric boundary layer for twenty-four hours. We employ a laser at a wavelength of 266 nm and detects the light separated into an elastic backscatter signal and vibrational Raman signals of oxygen, nitrogen, and water vapor. The lidar was encased in a temperature-controlled and vibration-isolated compact container, resistant to a variety of environmental conditions. Water vapor profile observations were made for twelve months from November 24, 2017, to November 29, 2018. These observations were compared with collocated radiosonde measurements for daytime and nighttime conditions.

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