Water vapor density and turbulent fluxes from three generations of infrared gas analyzers

Abstract. Fast-response infrared gas analyzers (IRGAs) have been widely used over 3 decades in many ecosystems for long-term monitoring of water vapor fluxes in the surface layer of the atmosphere. While some of the early IRGA sensors are still used in these national and/or regional eco-flux networks, optically improved IRGA sensors are newly employed in the same networks. The purpose of this study was to evaluate the performance of water vapor density and flux data from three generations of IRGAs – LI-7500, LI-7500A, and LI-7500RS (LI-COR Bioscience, Inc., Nebraska, USA) – over the course of a growing season in Bushland, Texas, USA, in an irrigated maize canopy for 90 d. Water vapor density measurements were in generally good agreement, but temporal drift occurred in different directions and magnitudes. Means exhibited mostly shift changes that did not impact the flux magnitudes, while their variances of water vapor density fluctuations were occasionally in poor agreement, especially following rainfall events. LI-7500 cospectra were largest compared to LI-7500RS and LI-7500A, especially under unstable and neutral static stability. Agreement among the sensors was best under the typical irrigation-cooled boundary layer, with a 14 % interinstrument coefficient of variability under advective conditions. Generally, the smallest variances occurred with the LI-7500RS, and high-frequency spectral corrections were larger for these measurements, resulting in similar fluxes between the LI-7500A and LI-7500RS. Fluxes from the LI-7500 were best representative of growing season ET based on a world-class lysimeter reference measurement, but using the energy balance ratio as an estimate of systematic bias corrected most of the differences among measured fluxes.

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Water vapor density and turbulent fluxes from three generations of infrared gas analyzers

10.5194/amt-2020-302 ◽

2020 ◽

Author(s):

Seth Kutikoff ◽

Xiaomao Lin ◽

Steven R. Evett ◽

Prasanna Gowda ◽

David Brauer ◽

...

Keyword(s):

Water Vapor ◽

Energy Balance ◽

Growing Season ◽

Fast Response ◽

Static Stability ◽

Turbulent Fluxes ◽

Density Fluctuations ◽

Systematic Bias ◽

Vapor Density ◽

Three Generations

Abstract. Fast-response infrared gas analyzers (IRGAs) have been widely used over three decades in many ecosystems for long-term monitoring of water vapor fluxes in the surface layer of the atmosphere. While some of the early IRGA sensors are still used in these national and/or regional eco-flux networks, optically-improved IRGA sensors are newly employed in the same networks. The purpose of this study was to evaluate the performance of water vapor density and flux data from three generations of IRGAs – LI-7500, LI-7500A, and LI-7500RS (LI-COR Bioscience, Inc., Nebraska, USA) – over the course of a growing season in Bushland, Texas, USA in an irrigated maize canopy for 90 days. The energy balance ratio, which is the sum of turbulent fluxes divided by the sum of surface available energy, was used to assess systematic biases of the IRGA sensors for evapotranspiration (ET). Water vapor density measurements were in generally good agreement, but temporal drift occurred in different directions and magnitudes. Means exhibited mostly shift changes that did not impact the flux magnitudes, while variances of water vapor density fluctuations were occasionally in poor agreement, especially following rainfall events. LI-7500 variances were largest compared to recent LI-7500RS and LI-7500A results manifesting in widened cospectra, especially under unstable and neutral static stability. Agreement among the sensors was best under the typical irrigation-cooled boundary layer, with a 14 % interinstrument coefficient of variability under advective conditions. Generally, the smallest variances occurred with the LI-7500RS, and high-frequency spectral corrections were larger for these measurements resulting in similar fluxes between the LI-7500A and LI-7500RS. Fluxes from the LI-7500 were best representative of growing season ET based on a world-class lysimeter reference measurement but using the energy balance ratio as an estimate of systematic bias corrected most of the differences among measured fluxes.

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Evaluation of Precipitable Water Vapor Retrieval from Homogeneously Reprocessed Long-Term GNSS Tropospheric Zenith Wet Delay and Multi-Technique

Remote Sensing ◽

10.3390/rs13214490 ◽

2021 ◽

Vol 13 (21) ◽

pp. 4490

Author(s):

Hang Su ◽

Tao Yang ◽

Kan Wang ◽

Baoqi Sun ◽

Xuhai Yang

Keyword(s):

Water Vapor ◽

Precipitable Water ◽

Precipitable Water Vapor ◽

Systematic Bias ◽

Navigation Satellite ◽

A Posteriori ◽

Zenith Wet Delay ◽

Global Navigation ◽

Global Navigation Satellite

Water vapor is one of the most important greenhouse gases in the world. There are many techniques that can measure water vapor directly or remotely. In this work, we first study the Global Positioning System (GPS)- and the Global Navigation Satellite System (GLONASS)-derived Zenith Wet Delay (ZWD) time series based on 11 years of the second reprocessing campaign of International Global Navigation Satellite Systems (GNSS) Service (IGS) using 320 globally distributed stations. The amount of measurement, the local environment, and the antenna radome are shown to be the main factors that affect the GNSS ZWDs and the corresponding a posteriori formal errors. Furthermore, antenna radome is able to effectively reduce the systematic bias of ZWDs and a posteriori formal errors between the GPS- and GLONASS-based solutions. With the development of the GLONASS, the ZWD differences between the GPS- and the GLONASS-based solutions have gradually decreased to sub-mm-level after GLONASS was fully operated. As the GPS-based Precipitable Water Vapor (PWV) is usually used as the reference to evaluate the other PWV products, the PWV consistency among several common techniques is evaluated, including GNSSs, spaceborne sensors, and numerical products from the European Center for Medium-Range Weather Forecasts (ECMWF). As an example of the results from a detailed comparison analysis, the long-term global analysis shows that the PWV obtained from the GNSS and the ECMWF have great intra-agreements. Based on the global distribution of the magnitude of the PWV and the PWV drift, most of the techniques showed superior agreement and proved their ability to do climate research. With a detailed study performed for the ZWDs and PWV on a long-term global scale, this contribution provides a useful supplement for future research on the GNSS ZWD and PWV.

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Faculty Opinions recommendation of Partitioning evapotranspiration using long-term carbon dioxide and water vapor fluxes.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.727830085.793534790 ◽

2017 ◽

Author(s):

Dennis Baldocchi

Keyword(s):

Carbon Dioxide ◽

Water Vapor

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Evaluation of long-term climate change impact on the growing season and water use of mature pecan in Lower Rio Grande Valley

Agricultural Water Management ◽

10.1016/j.agwat.2021.106893 ◽

2021 ◽

Vol 252 ◽

pp. 106893

Author(s):

Esmaiil Mokari ◽

Zohrab Samani ◽

Richard Heerema ◽

Frank Ward

Keyword(s):

Climate Change ◽

Water Use ◽

Climate Change Impact ◽

Rio Grande Valley ◽

Rio Grande ◽

Growing Season ◽

Lower Rio Grande Valley ◽

Change Impact ◽

Lower Rio Grande

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Estimating Water Vapor Using Signals from Microwave Links below 25 GHz

Remote Sensing ◽

10.3390/rs13081409 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1409

Author(s):

Kun Song ◽

Xichuan Liu ◽

Taichang Gao ◽

Peng Zhang

Keyword(s):

Water Vapor ◽

Weather Forecasting ◽

Water Cycle ◽

Correlation Coefficients ◽

Support Vector ◽

Vapor Density ◽

Measurement Resolution ◽

Sensing Model ◽

Numerical Weather Forecasting ◽

Mean Square Errors

Water vapor is a key element in both the greenhouse effect and the water cycle. However, water vapor has not been well studied due to the limitations of conventional monitoring instruments. Recently, estimating rain rate by the rain-induced attenuation of commercial microwave links (MLs) has been proven to be a feasible method. Similar to rainfall, water vapor also attenuates the energy of MLs. Thus, MLs also have the potential of estimating water vapor. This study proposes a method to estimate water vapor density by using the received signal level (RSL) of MLs at 15, 18, and 23 GHz, which is the first attempt to estimate water vapor by MLs below 20 GHz. This method trains a sensing model with prior RSL data and water vapor density by the support vector machine, and the model can directly estimate the water vapor density from the RSLs without preprocessing. The results show that the measurement resolution of the proposed method is less than 1 g/m3. The correlation coefficients between automatic weather stations and MLs range from 0.72 to 0.81, and the root mean square errors range from 1.57 to 2.31 g/m3. With the large availability of signal measurements from communications operators, this method has the potential of providing refined data on water vapor density, which can contribute to research on the atmospheric boundary layer and numerical weather forecasting.

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Photocatalytic Activity Enhancement of Low-pressure Cold-Sprayed TiO2 Coatings Induced by Long-term Water Vapor Exposure

Journal of Thermal Spray Technology ◽

10.1007/s11666-021-01244-5 ◽

2021 ◽

Cited By ~ 1

Author(s):

Seremak Wioletta ◽

Baszczuk Agnieszka ◽

Jasiorski Marek ◽

Gibas Anna ◽

Winnicki Marcin

Keyword(s):

Titanium Dioxide ◽

Photocatalytic Activity ◽

Water Vapor ◽

Sol Gel ◽

Low Pressure ◽

Oxygen Depletion ◽

Amorphous Structure ◽

Industrial Applications ◽

Additional Parameter

AbstractThis work shows that the titanium dioxide coatings obtained by low-pressure cold gas spraying with the use of the sol–gel amorphous TiO2 powder are characterized by photocatalytic activity despite their partial amorphous content. Moreover, the research outcome suggests that the decomposition rate of organic pollutants is enhanced after long-term exposure to moisture. The condensation humidity test is not detrimental to the continuity and integrity of the coating, but the phase composition of coatings changes—with the exposure to water vapor, the portion of the amorphous phase crystallizes into brookite. The mechanism responsible for the conversion of amorphous TiO2 into brookite is attributed to the water-driven dissolution and reprecipitation of TiO6 octahedra. It has been shown that an additional parameter necessary for the stabilization of the brookite is the oxygen depletion of the amorphous structure of titanium dioxide. Considering the results presented in this paper and the advantages of a portable, low-pressure cold spray system for industrial applications, it is expected that TiO2 coatings produced from a sol–gel feedstock powder can be further developed and tested as efficient photocatalysts.

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Long-term experimentally deepened snow decreases growing-season respiration in a low- and high-arctic tundra ecosystem

Journal of Geophysical Research Biogeosciences ◽

10.1002/2015jg003251 ◽

2016 ◽

Vol 121 (5) ◽

pp. 1236-1248 ◽

Cited By ~ 16

Author(s):

Philipp R. Semenchuk ◽

Casper T. Christiansen ◽

Paul Grogan ◽

Bo Elberling ◽

Elisabeth J. Cooper

Keyword(s):

Growing Season ◽

Arctic Tundra ◽

High Arctic ◽

Tundra Ecosystem

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Long-term follow-up of former world-class swimmers: evaluation of cardiovascular function

Heart and Vessels ◽

10.1007/s00380-014-0481-z ◽

2014 ◽

Vol 30 (3) ◽

pp. 369-378 ◽

Cited By ~ 4

Author(s):

Christian Knackstedt ◽

Klaus Schmidt ◽

Lukas Syrocki ◽

Andreas Lang ◽

Birna Bjarnason-Wehrens ◽

...

Keyword(s):

Cardiovascular Function ◽

Long Term Follow Up ◽

World Class

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Walleye (Stizostedion vitreum vitreum) and Yellow Perch (Perca flavescens) Populations and Fisheries of the Red Lakes, Minnesota, 1930–75

Journal of the Fisheries Research Board of Canada ◽

10.1139/f77-243 ◽

1977 ◽

Vol 34 (10) ◽

pp. 1774-1783 ◽

Cited By ~ 9

Author(s):

Lloyd L. Smith Jr.

Keyword(s):

Growth Rate ◽

Yellow Perch ◽

Climatic Factors ◽

Perca Flavescens ◽

Growing Season ◽

Commercial Fishery ◽

Class Strength ◽

Parent Stock ◽

Catch Statistics

In an investigation of the commercial fishery of Red Lakes, Minnesota, for the 46-yr period 1930–75, catch statistics were analyzed, and the dynamics of the perch and walleye populations were examined. Mean annual yields of walleye for two statistical periods, 1930–53 and 1954–75, were 309,900 and 245,100 kg, respectively for walleyes, and 96,400 and 109,500 kg for perch. Annual abundance (CPE based on average catches per day per 5-net units of gill nets) varied from 3.8 to 64.6 kg for walleye, and from 2.5 to 34.4 kg for perch. Causes of fluctuations in harvestable stock were directly related to strength of year-classes and to growth rate during the season of capture. Year-class strength was not related to the abundance of parent stock or of potential predators. The respective strengths of year-classes of perch and walleye in the same year were positively correlated (r = 0.859, P < 0.01), and are directly related to climatic factors. Growth rate of walleye in different calendar years varied from +30.7 to −42.2% of mean growth, and that of perch from +13.4 to −8.6% (1941–56). Growing season began in mid-June and was almost over by September 1. Walleye yield could be enhanced by starting harvest July 1 instead of early June. Perch yield could be improved by harvesting small perch. Key words: Percidae, Perca, population dynamics, Stizostedion, long-term yield

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