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Scintillometer

About: Scintillometer is a research topic. Over the lifetime, 650 publications have been published within this topic receiving 11776 citations.


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TL;DR: In this article, the seasonal variations of energy balance components over three different surfaces: irrigated cropland (Yingke, YK), alpine meadow (A'rou, AR), and spruce forest (Guantan, GT) were analyzed.
Abstract: . We analyzed the seasonal variations of energy balance components over three different surfaces: irrigated cropland (Yingke, YK), alpine meadow (A'rou, AR), and spruce forest (Guantan, GT). The energy balance components were measured using eddy covariance (EC) systems and a large aperture scintillometer (LAS) in the Heihe River Basin, China, in 2008 and 2009. We also determined the source areas of the EC and LAS measurements with a footprint model for each site and discussed the differences between the sensible heat fluxes measured with EC and LAS at AR. The results show that the main EC source areas were within a radius of 250 m at all of the sites. The main source area for the LAS (with a path length of 2390 m) stretched along a path line approximately 2000 m long and 700 m wide. The surface characteristics in the source areas changed with the season at each site, and there were characteristic seasonal variations in the energy balance components at all of the sites. The sensible heat flux was the main term of the energy budget during the dormant season. During the growing season, however, the latent heat flux dominated the energy budget, and an obvious "oasis effect" was observed at YK. The sensible heat fluxes measured by LAS at AR were larger than those measured by EC at the same site. This difference seems to be caused by the so-called energy imbalance phenomenon, the heterogeneity of the underlying surfaces, and the difference between the source areas of the LAS and EC measurements.

444 citations

Journal ArticleDOI
TL;DR: In this article, a semi-empirical theory is developed which relates the refractive index-structure parameter Cn2 in the lowest few tens of meters to the vertical gradients of wind speed and temperature and to a stability parameter.
Abstract: A semiempirical theory is developed which relates the refractive-index-structure parameter Cn2 in the lowest few tens of meters to the vertical gradients of wind speed and temperature and to a stability parameter. This provides an indirect method of determining Cn2, or its temperature counterpart CT2, and the method is successfully applied to recent data which include directly measured CT2 values. The height dependence of the structure parameter is also determined, and the predicted z−4/3 profile under unstable conditions agrees with recent data in the free atmosphere at heights up to 500 m.

392 citations

Journal ArticleDOI
TL;DR: In this article, a set of micro-meteorological data collected over a horizontal, uniform terrain (the plain of La Crau, France) in June 1987 is analyzed.
Abstract: A set of micro-meteorological data collected over a horizontal, uniform terrain (the plain of La Crau, France) in June 1987 is analysed. Conditions were predominantly sunny and arid, while due to the “Mistral” the wind speed could exceed 10 m/s. Verification of several methods to evaluate surface fluxes of heat, momentum and water vapour from the standard deviation of temperature, wind and specific humidity is presented. Also, a similar approach using the structure parameter of temperature is considered. These methods are all based on Monin-Obukhov (M-O) similarity theory. It is found that the standard deviation of temperature, vertical and horizontal wind speed as well as the structure parameter for temperature behave according to M-O similarity. It is shown that the sensible heat flux and friction velocity can be determined from a fast response thermometer and a cup anemometer. Also, it appears that the analytic solution of the set of governing equations as derived by the first author yields good results. M-O theory does not appear to work for the standard deviation of specific humidity. This may be due to the relative importance of large eddies.

295 citations

Journal ArticleDOI
TL;DR: In this article, a multi-scale observation experiment on evapotranspiration over heterogeneous land surfaces of The Heihe Watershed Allied Telemetry Experimental Research (HiWATER-MUSOEXE) was conducted, particularly in regard to radiation and turbulent flux measurements.
Abstract: [1] Agreement among instruments is very important for the Multi-Scale Observation Experiment on Evapotranspiration over heterogeneous land surfaces of The Heihe Watershed Allied Telemetry Experimental Research (HiWATER-MUSOEXE), particularly in regard to radiation and turbulent flux measurements Before HiWATER-MUSOEXE was conducted, 20 eddy covariance (EC) system sets, 18 radiometer sets, and seven large aperture scintillometers (LASs) sets were intercompared over the Gobi desert between 14 and 24 May 2012 For radiometers, the four-component radiation measurements exhibited good agreement—the average root-mean-square error (RMSE) and mean relative error (MRE) for the net radiation were 1038 W m−2 and 124%, respectively With regard to the EC systems, the best consistency for sensible heat fluxes was found among CSAT3 sonic anemometers and Li7500A/Li7500/EC150 combinations (average RMSE, 1230 W m−2 and MRE, −136%), followed by Gill sonic anemometers and Li7500A/Li7500 combinations when a proper angle of attack correction method was applied (average RMSE, 1675 W m−2 and MRE, −552%) The sensible heat flux measured using different LASs agreed well with high correlation coefficients—the average RMSE and MRE values were 1026 W m−2 and 548% for boundary layer scintillometer (BLS) 900, 1632 W m−2 and 1047% for BLS450, and 1438 W m−2 and −372% for ZZLAS, respectively The EC and LAS measurements were compared and agreed well over homogeneous underlying surfaces, which also indicated that the EC and LAS measurements would be comparable in the follow-up experiment The intercomparison results can be used to determine instrument placement and are very helpful for subsequent data analysis

255 citations

Journal ArticleDOI
TL;DR: In this paper, a new optical technique for measuring the refractive-index structure parameter Cn2 was described, using relatively large incoherent transmitting and receiving optics, the scintillometer maintains its calibration and path-weighting function throughout the range of observed refractive turbulence values, even to the case of saturated scintillation.
Abstract: This paper describes a new optical technique for measuring the refractive-index structure parameter Cn2. By using relatively large incoherent transmitting and receiving optics, the scintillometer maintains its calibration and path-weighting function throughout the range of observed refractive turbulence values, even to the case of saturated scintillation.

237 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202313
202229
20218
20209
20199
201816