Wind Variations along a Glide Path

1968 ◽  
Vol 21 (2) ◽  
pp. 221-225 ◽  
Author(s):  
T. W. Harrold ◽  
K. A. Browning
Keyword(s):  
Doppler Radar ◽  
Horizontal Wind ◽  
Line Of Sight ◽  
Wind Component ◽  
Pulsed Doppler ◽  
Glide Path

A method of measuring wind variations along an aircraft glide path is described. The technique uses a ground-based pulsed doppler radar to measure the line of sight velocity of precipitation particles. At low angles of elevation this velocity is that of die horizontal wind component toward the radar.Wind variations likely to be encountered by an aircraft as it lands or takes off from an airfield are estimated almost invariably from a nearby anemometer placed 10 m. above the ground. It is obvious that this wind is not fully representative of conditions at higher levels; however, winds other than near the ground are difficult to measure. This note describes a method of measuring the line of sight wind using a pulsed doppler radar and presents some observations of the wind variation along a path at an elevation of 3°, which is typical of the glide path of many aircraft. These winds are compared with those recorded by a nearby anemometer.

scholarly journals On the derivation of zonal and meridional wind components from Aeolus horizontal line-of-sight wind

2021 ◽  
Author(s):  
Isabell Krisch ◽  
Neil P. Hindley ◽  
Oliver Reitebuch ◽  
Corwin J. Wright
Keyword(s):  
Lower Stratosphere ◽  
Weather Prediction ◽  
Meridional Wind ◽  
Atmospheric Dynamics ◽  
Horizontal Wind ◽  
Line Of Sight ◽  
Wind Component ◽  
Horizontal Line ◽  
Sigma Level ◽  
Wind Measurements

Abstract. Since its launch in 2018, the European Space Agency’s Earth Explorer satellite Aeolus has provided global height resolved measurements of horizontal wind in the troposphere and lower stratosphere for the first time. Novel datasets such as these provide an unprecedented opportunity for the research of atmospheric dynamics and provide new insights into the dynamics of the upper troposphere and lower stratosphere (UTLS) region. Aeolus measures the wind component along its horizontal line-of-sight, but for the analysis and interpretation of atmospheric dynamics, zonal and/or meridional wind components are most useful. In this paper, we introduce and compare three different methods to derive zonal and meridional wind components from the Aeolus wind measurements. We find that the most promising method involves combining Aeolus measurements during ascending and descending orbits. Using this method, we derive global estimates of the zonal wind in the latitude range 79.7° S to 84.5° N with errors of less than 5 ms−1 (at the 2-sigma level). Due to the orbit geometry of Aeolus, the estimation of meridional wind in the tropics and at midlatitudes is more challenging and the quality is less reliable. However, we find that it is possible to derive meridional winds poleward of 70° latitude with absolute errors typically below ±5 ms−1 (at the 2-sigma level). This further demonstrate the value of Aeolus wind measurements for applications in weather and climate research, in addition to their important role in numerical weather prediction.

scholarly journals The Coplane Analysis Technique for Three-Dimensional Wind Retrieval Using the HIWRAP Airborne Doppler Radar

2015 ◽  
Vol 54 (3) ◽  
pp. 605-623 ◽  
Author(s):  
Anthony C. Didlake ◽  
Gerald M. Heymsfield ◽  
Lin Tian ◽  
Stephen R. Guimond
Keyword(s):  
Global Optimization ◽  
Doppler Radar ◽  
Three Dimensional ◽  
Optimization Method ◽  
Vertical Wind ◽  
Wind Component ◽  
Global Optimization Method ◽  
Analysis Technique ◽  
Radar Measurements ◽  
Cross Track

AbstractThe coplane analysis technique for mapping the three-dimensional wind field of precipitating systems is applied to the NASA High-Altitude Wind and Rain Airborne Profiler (HIWRAP). HIWRAP is a dual-frequency Doppler radar system with two downward-pointing and conically scanning beams. The coplane technique interpolates radar measurements onto a natural coordinate frame, directly solves for two wind components, and integrates the mass continuity equation to retrieve the unobserved third wind component. This technique is tested using a model simulation of a hurricane and compared with a global optimization retrieval. The coplane method produced lower errors for the cross-track and vertical wind components, while the global optimization method produced lower errors for the along-track wind component. Cross-track and vertical wind errors were dependent upon the accuracy of the estimated boundary condition winds near the surface and at nadir, which were derived by making certain assumptions about the vertical velocity field. The coplane technique was then applied successfully to HIWRAP observations of Hurricane Ingrid (2013). Unlike the global optimization method, the coplane analysis allows for a transparent connection between the radar observations and specific analysis results. With this ability, small-scale features can be analyzed more adequately and erroneous radar measurements can be identified more easily.

scholarly journals Combined wind profiler-weather radar observations of orographic rainband around Kyushu, Japan in the Baiu season

2004 ◽  
Vol 22 (11) ◽  
pp. 3971-3982 ◽  
Author(s):  
Y. Umemoto ◽  
M. Teshiba ◽  
Y. Shibagaki ◽  
H. Hashiguchi ◽  
M. D. Yamanaka ◽  
...  
Keyword(s):  
Weather Radar ◽  
Horizontal Wind ◽  
Wind Component ◽  
Wind Profiler ◽  
Strong Wind ◽  
Clockwise Rotation ◽  
Weather Radars ◽  
X Band ◽  
Western Japan ◽  
Lifting Condensation Level

Abstract. A special observation campaign (X-BAIU), using various instruments (wind profilers, C-band weather radars, X-band Doppler radars, rawinsondes, etc.), was carried out in Kyushu (western Japan) during the Baiu season, from 1998 to 2002. In the X-BAIU-99 and -02 observations, a line-shaped orographic rainband extending northeastward from the Koshikijima Islands appeared in the low-level strong wind with warm-moist airs. The weather radar observation indicated that the rainband was maintained for 11h. The maximum length and width of the rainband observed in 1999 was ~200km and ~20km, respectively. The rainband observed in 2002 was not so developed compared with the case in 1999. The Froude number averaged from sea level to the top of the Koshikijima Islands (~600m) was large (>1), and the lifting condensation level was below the tops of the Koshikijima Islands. Thus, it is suggested that the clouds organizing the rainband are formed by the triggering of the mountains on the airflow passing over them. The vertical profile of horizontal wind in/around the rainband was investigated in the wind profiler observations. In the downdraft region 60km from the Koshikijima Islands, strong wind and its clockwise rotation with increasing height was observed below 3km altitude. In addition, a strong wind component perpendicular to the rainband was observed when the rainband was well developed. These wind behaviors were related to the evolution of the rainband.

scholarly journals Simulation study for the Stratospheric Inferred Winds (SIW) sub-millimeter limb sounder

2018 ◽  
Author(s):  
Philippe Baron ◽  
Donal Murtagh ◽  
Patrick Eriksson ◽  
Jana Mendrok ◽  
Satoshi Ochiai ◽  
...  
Keyword(s):  
Simulation Study ◽  
Spectral Band ◽  
Chemical Species ◽  
Field Of View ◽  
Emission Lines ◽  
Horizontal Wind ◽  
Line Of Sight ◽  
Heterodyne Receiver ◽  
Vertical Field ◽  
Wind Measurements

Abstract. Stratospheric Inferred Winds (SIW) is a Swedish mini sub-millimeter limb sounder selected for the 2nd InnoSat platform launch planned near 2022. It is intended to fill the altitude gap between 30–70 km in atmospheric wind measurements and also aims at pursuing the limb observations of temperature and key atmospheric constituents between 10–90 km when current satellite missions are probably stopped. Line-of-sight winds are retrieved from the Doppler shift of the emission lines introduced by 5 the wind field. Observations will be performed with two antennas pointing toward the limb with perpendicular directions to reconstruct the 2-D horizontal wind vector. Each antenna has a vertical field of view of 5 km. The chosen spectral band near 655 GHz contains a dense group of strong O3 lines suitable for exploiting the small wind information in stratospheric spectra. Using both sidebands of the heterodyne receiver, a large number of chemical species will be measured including O3-isopotologues, H2O, HDO, HCl, ClO, N2O, HNO3, NO, NO2, HCN, CH3CN and HO2. This paper presents the simulation study for assessing the measurement performances. The line-of-sight winds are retrieved between 30–90 km with the best sensitivity between 35–70 km where the precision (1-sigma) is 5–10 m s−1 for a single scan. Similar performances can be obtained during day and night conditions except in the lower mesosphere where the photo-dissociation of O3 in day-time reduces the sensitivity by 50 % near 70 km. Profiles of O3, H2O and temperature are retrieved with a high precision up to 50 km (

scholarly journals Radar Kinematic Information as a Surrogate for Isentropes in Stratiform Precipitation Systems

2017 ◽  
Vol 145 (9) ◽  
pp. 3763-3774 ◽  
Author(s):  
Bart Geerts ◽  
Jordan I. Christian
Keyword(s):  
Wind Shear ◽  
Doppler Radar ◽  
Potential Temperature ◽  
Vertical Gradient ◽  
Horizontal Wind ◽  
Model Output ◽  
Vertical Resolution ◽  
Equivalent Potential ◽  
Stratiform Precipitation ◽  
Kinematic Information

Abstract This study illustrates that dual-Doppler-derived wind shear (vertical gradient of the horizontal wind) in stratiform, nonturbulent flow is structured in long, thin striations. The reason this has not been documented before is that scanning ground-based radars have inadequate vertical resolution, deteriorating with range. Here data from an airborne radar with a fine, range-independent vertical resolution are used. A comparison of the radar-derived wind shear with model output of isentropes in vertical transects in the comma head of two frontal disturbances suggests that the wind shear layers describe material surfaces. Model output itself further confirms the alignment of isentropes with wind shear in vertical transects. Thus, Doppler-radar-derived wind shear (a kinematic conserved variable) may serve as a suitable proxy for thermodynamic conserved variables such as equivalent potential temperature in stratiform precipitation. Furthermore, the presence of shear striations in vertical transects can be used as a marker for nonturbulent flow, and their persistence as an indicator of limited dispersion in such flow.

scholarly journals Moving Cellular Structure of Fog Echoes Obtained with a Millimeter-Wave Scanning Doppler Radar at Kushiro, Japan

2005 ◽  
Vol 44 (8) ◽  
pp. 1260-1273 ◽  
Author(s):  
Akihisa Uematsu ◽  
Hiroyuki Hashiguchi ◽  
Michihiro Teshiba ◽  
Hisamichi Tanaka ◽  
Koichi Hirashima ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Cellular Structure ◽  
Doppler Radar ◽  
Radar Reflectivity ◽  
Vertical Shear ◽  
Horizontal Wind ◽  
Shear Line ◽  
Position Indicator ◽  
Advection Fog

Abstract Observations of fogs with a millimeter-wave scanning Doppler radar were conducted at Kushiro in Hokkaido, Japan, in the summer seasons of 1999 and 2000. Three typical types of plan position indicator (PPI) displays were observed: cellular echoes with high radar reflectivity factors (∼−10 dBZ), uniformly distributed echoes with high reflectivities (∼−10 dBZ), and uniformly distributed echoes with low reflectivities (∼−30 dBZ). The authors focused on advection fog with cellular echoes observed on 5 August 1999 and 31 July 2000. Echoes showed structures of cells with a reflectivity of −10 dBZ and with intervals of about 1 km. This echo pattern moved northward (i.e., from the sea to the land). There was a vertical shear of the horizontal wind at a height around 200 m in both cases, and structures of each cell were upright above the shear line and were leaning below it. The direction and the speed of the echo pattern in both PPI and range–height indicator (RHI) displays agreed well with that of the horizontal wind at heights above the shear (200 m). In the echo cells, existence of drizzle drops is implied.

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