Measurement of the atmospheric boundary-layer resistance law for water vapor

1985 ◽  
Vol 33 (2) ◽  
pp. 105-111 ◽  
Author(s):  
L. O. Myrup ◽  
C. D. Johnson ◽  
W. O. Pruitt
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Atmospheric Boundary Layer ◽  
Layer Resistance ◽  
Boundary Layer Resistance

Genotypic Variation in Carbon Isotope Discrimination and Transpiration Efficiency in Wheat. Leaf Gas Exchange and Whole Plant Studies

1990 ◽  
Vol 17 (1) ◽  
pp. 9 ◽  
Author(s):  
AG Condon ◽  
GD Farquhar ◽  
RA Richards
Keyword(s):  
Boundary Layer ◽  
Water Loss ◽  
Dry Matter ◽  
Carbon Isotope Discrimination ◽  
Genotypic Variation ◽  
Transpiration Efficiency ◽  
Layer Resistance ◽  
Boundary Layer Resistance ◽  
The Relationship ◽  
Canopy Water

The relationship between carbon isotope discrimination, Δ, measured in plant dry matter and the ratio of intercellular to atmospheric partial pressures of CO2, pi/pa, in leaves was examined in two glasshouse experiments using 14 wheat genotypes selected on the basis of variation in Δ of dry matter. Genotypic variation in Δ was similar in both experiments, with an average range of 1.8 x 10-3. Variation in pi/pa was significant but the range in pi/pa was relatively small, averaging 0.075. In both experiments, Δ measured in dry matter and pi/pa measured in flag leaves were positively correlated. Variation among genotypes in pi/pa was attributed, approximately equally, to variation in leaf conductance and in photosynthetic capacity. The relationship between plant transpiration efficiency, W* (the amount of above-ground dry matter produced per unit water transpired) and � was also examined. There was a negative correlation between W * and Δ; under well watered conditions and under gradually increasing terminal water stress. The relationship between W* of stressed plants and Δ measured in well watered plants was also negative. These results indicate that genotypic variation in Δ measured in dry matter should provide a reasonable measure of genotypic variation in long-term mean leaf pi/pa in wheat. Further, selection for improved plant transpiration efficiency in wheat under both well watered and terminally water- stressed conditions should be possible based on Δ measured in well watered plants. The extent to which such selection will be effective in improving transpiration efficiency at the field canopy level may depend on the influence of boundary layer resistance on transpirationsal water loss. Under well watered conditions and at full canopy closure, the influence of boundary layer resistance on canopy water loss may be relatively large and stomatal control of water loss may be limited. Under water stress, stomatal control of canopy water loss will be greater.

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

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 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.

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

2016 ◽  
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.

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

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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