scholarly journals Application of aerological radar to determine the wind profile in the lower troposphere

2021 ◽  
Vol 5 (1) ◽  
pp. 32-48
Author(s):  
I. V. Bukrin ◽  
◽  
A. V. Gusev ◽  
S. I. Kudinov ◽  
V. E. Ivanov ◽  
...  
Keyword(s):  
Wind Profile ◽  
Meteorological Parameters ◽  
Operation Mode ◽  
Lower Troposphere ◽  
Vertical Wind ◽  
Doppler Spectrum ◽  
Free Atmosphere ◽  
Climate Forecasts ◽  
Angular Coordinates ◽  
Sky Conditions

Currently, radar and radionavigation systems for aerological sounding of the atmosphere with the help of aerological radiosondes launched into the atmosphere are widely used to provide operational weather and climate forecasts. Meteorological radar systems for various purposes have been developed to obtain operational data on the free atmosphere. The systems are operated, providing measurement of meteorological parameters by noncontact methods. One of the most important meteorological parameters is the vertical wind profile. Specialized radars have been created to determine the distribution of wind direction and speed by altitude. They allow measuring the dynamic parameters of the wind in real time. The article considers the possibility of creating a radar for the wind parameters measuring the lower troposphere based on the modernization of a serial domestic aerological radar. Technical characteristics of the radar such as the pulse transmitting power, the sensitivity of the receiver, the ability to control the antenna radiation pattern accurately by angular coordinates make it possible to provide fundamental wind measurement in the lower troposphere. The main issues of modernization are related to the need of implementation of the coherent operation mode into the radar receiver and transmitter and ensuring the coherent energy storage of the reflected signal during the interval of statistical stability of the atmosphere. The information about the wind at the measured altitude is estimated from the Doppler spectrum of the signal reflected from meteorological inhomogeneities. The ability to accurately point the antenna during the sounding session allows determination of the vertical wind profile in the altitude range, even in clear sky conditions.

scholarly journals The global 3-D distribution of tropospheric aerosols as characterized by CALIOP

2013 ◽  
Vol 13 (6) ◽  
pp. 3345-3361 ◽  
Author(s):  
D. M. Winker ◽  
J. L. Tackett ◽  
B. J. Getzewich ◽  
Z. Liu ◽  
M. A. Vaughan ◽  
...  
Keyword(s):  
Lower Troposphere ◽  
Aerosol Extinction ◽  
Transport Pathways ◽  
3 Dimensional ◽  
Clear Sky ◽  
Tropospheric Aerosol ◽  
Vertical Distributions ◽  
Dimensional Distribution ◽  
Level 3 ◽  
Sky Conditions

Abstract. The CALIOP lidar, carried on the CALIPSO satellite, has been acquiring global atmospheric profiles since June 2006. This dataset now offers the opportunity to characterize the global 3-D distribution of aerosol as well as seasonal and interannual variations, and confront aerosol models with observations in a way that has not been possible before. With that goal in mind, a monthly global gridded dataset of daytime and nighttime aerosol extinction profiles has been constructed, available as a Level 3 aerosol product. Averaged aerosol profiles for cloud-free and all-sky conditions are reported separately. This 6-yr dataset characterizes the global 3-dimensional distribution of tropospheric aerosol. Vertical distributions are seen to vary with season, as both source strengths and transport mechanisms vary. In most regions, clear-sky and all-sky mean aerosol profiles are found to be quite similar, implying a lack of correlation between high semi-transparent cloud and aerosol in the lower troposphere. An initial evaluation of the accuracy of the aerosol extinction profiles is presented. Detection limitations and the representivity of aerosol profiles in the upper troposphere are of particular concern. While results are preliminary, we present evidence that the monthly-mean CALIOP aerosol profiles provide quantitative characterization of elevated aerosol layers in major transport pathways. Aerosol extinction in the free troposphere in clean conditions, where the true aerosol extinction is typically 0.001 km−1 or less, is generally underestimated, however. The work described here forms an initial global 3-D aerosol climatology which we plan to extend and improve over time.

Meteorological Parameters Affecting Supersonic Transport Operations

1967 ◽  
Vol 20 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Richard Scherhag ◽  
Gunter Warnecke ◽  
Werner Wehry
Keyword(s):  
Working Group ◽  
Meteorological Parameters ◽  
Sonic Boom ◽  
Atmospheric Ozone ◽  
Atmospheric Conditions ◽  
Atmospheric Parameters ◽  
Free Atmosphere ◽  
Supersonic Transport ◽  
Supersonic Aircraft ◽  
Initial Task

In 1965, following the Eastbourne Conference, the British, French and German Institutes of Navigation formed a Working Group to make a study of the environment in which the supersonic transport will operate and of its implications for the navigation of such aircraft. The Group's initial task has been one of education, largely through discussion of a series of papers submitted to it. Some of the papers considered have already been published in the Journal (Vol. 19) and a further selection is published below. Table I was contributed by Mr. G. E. Beck. The illustrations to these papers have not all been reproduced.1. Atmospheric Conditions. It will be useful to distinguish between different kinds of atmospheric influences on supersonic aircraft operations. They may be classed as follows:(a) Sporadic effects near the ground(b) Sporadic effects in the free atmosphere(c) Effects on sonic boom(d) Effects of atmospheric ozone(e) Permanently effective atmospheric parameters, such as temperature, density and wind.

Analysis of Vertical Wind Profile using LiDAR in Mountainous Terrain

2016 ◽  
Vol 2016 (0) ◽  
pp. J0550402 ◽  
Author(s):  
Satoshi NAKASHIMA ◽  
Hiroaki FUJIO ◽  
Nobutoshi NISHIO ◽  
Chuichi ARAKAWA ◽  
Makoto IIDA
Keyword(s):  
Wind Profile ◽  
Vertical Wind ◽  
Mountainous Terrain

scholarly journals The Influence of Uniform Flow on Tropical Cyclone Intensity Change

2005 ◽  
Vol 62 (9) ◽  
pp. 3193-3212 ◽  
Author(s):  
Joey H. Y. Kwok ◽  
Johnny C. L. Chan
Keyword(s):  
Tropical Cyclone ◽  
Wind Shear ◽  
Mesoscale Model ◽  
Vertical Wind Shear ◽  
Lower Troposphere ◽  
Vertical Motion ◽  
Uniform Flow ◽  
Vertical Wind ◽  
Intensity Change ◽  
Westerly Flow

Abstract The influence of a uniform flow on the structural changes of a tropical cyclone (TC) is investigated using the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5). Idealized experiments are performed on either an f plane or a β plane. A strong uniform flow on an f plane results in a weaker vortex due to the development of a vertical wind shear induced by the asymmetric vertical motion and a rotation of upper-level anticyclone. The asymmetric vertical motion also reduces the secondary circulation of the vortex. On a β plane with no flow, a broad anticyclonic flow is found to the southeast of the vortex, which expands with time. Similar to the f-plane case, asymmetric vertical motion and vertical wind shear are also found. This beta-induced shear weakens the no-flow case significantly relative to that on an f plane. When a uniform flow is imposed on a β plane, an easterly flow produces a stronger asymmetry whereas a westerly flow reduces it. In addition, an easterly uniform flow tends to strengthen the beta-induced shear whereas a westerly flow appears to reduce it by altering the magnitude and direction of the shear vector. As a result, a westerly flow enhances TC development while an easterly flow reduces it. The vortex tilt and midlevel warming found in this study agree with the previous investigations of vertical wind shear. A strong uniform flow with a constant f results in a tilted and deformed potential vorticity at the upper levels. For a variable f, such tilting is more pronounced for a vortex in an easterly flow, while a westerly flow reduces the tilt. In addition, the vortex tilt appears to be related to the midlevel warming such that the warm core in the lower troposphere cannot extent upward, which leads to the subsequent weakening of the TC.

scholarly journals Measurements of Rainfall Velocity and Raindrop Size Distribution Using Coherent Doppler Lidar

2016 ◽  
Vol 33 (9) ◽  
pp. 1949-1966 ◽  
Author(s):  
Makoto Aoki ◽  
Hironori Iwai ◽  
Katsuhiro Nakagawa ◽  
Shoken Ishii ◽  
Kohei Mizutani
Keyword(s):  
Size Distribution ◽  
Wind Velocity ◽  
Vertical Wind ◽  
Doppler Spectrum ◽  
Doppler Lidar ◽  
Stratiform Rain ◽  
Raindrop Size Distribution ◽  
Raindrop Size ◽  
Rain Events ◽  
Vertical Wind Velocity

AbstractRainfall velocity, raindrop size distribution (DSD), and vertical wind velocity were simultaneously observed with 2.05- and 1.54-μm coherent Doppler lidars during convective and stratiform rain events. A retrieval method is based on identifying two separate spectra from the convolution of the aerosol and precipitation Doppler lidar spectra. The vertical wind velocity was retrieved from the aerosol spectrum peak and then the terminal rainfall velocity corrected by the vertical air motion from the precipitation spectrum peak was obtained. The DSD was derived from the precipitation spectrum using the relationship between the raindrop size and the terminal rainfall velocity. A comparison of the 1-min-averaged rainfall velocity from Doppler lidar measurements at a minimum range and that from a collocated ground-based optical disdrometer revealed high correlation coefficients of over 0.89 for both convective and stratiform rain events. The 1-min-averaged DSDs retrieved from the Doppler lidar spectrum using parametric and nonparametric methods are also in good agreement with those measured with the optical disdrometer with a correlation coefficient of over 0.80 for all rain events. To retrieve the DSD, the parametric method assumes a mathematical function for the DSD and the nonparametric method computes the direct deconvolution of the measured Doppler lidar spectrum without assuming a DSD function. It is confirmed that the Doppler lidar can retrieve the rainfall velocity and DSD during relatively heavy rain, whereas the ratio of valid data significantly decreases in light rain events because it is extremely difficult to separate the overlapping rain and aerosol peaks in the Doppler spectrum.

scholarly journals Some aspects of squall over Indira Gandhi International airport, New Delhi

MAUSAM ◽  
2021 ◽  
Vol 63 (4) ◽  
pp. 623-638
Author(s):  
SURESH RAM ◽  
M. MOHAPATRA
Keyword(s):  
Meteorological Parameters ◽  
Environmental Changes ◽  
Lower Troposphere ◽  
India Meteorological Department ◽  
Dew Point ◽  
New Delhi ◽  
Dry Air ◽  
Intensity Duration Frequency ◽  
Level Inversion ◽  
Period Of Occurrence

A study is undertaken to analyse the characteristics of squall over Delhi and to find out the potential precursors for its prediction. For this purpose, the squall data of Indira Gandhi International (IGI) airport along with the surface and upper air meteorological parameters recorded by India Meteorological Department have been considered for all individual months over the period of 2001-2010. Apart from the characteristics like period of occurrence, intensity, duration, frequency and nature of squall, the environmental changes due to squall and thermodynamic features and indices leading to squall have been analysed. Higher than normal warming of lower troposphere upto 700 hPa level in March, April & June and at 925 hPa in May accompanied with cold dry air advection leading to lower than normal dew point in middle and upper levels (500-300 hPa in March, May and June, 400-300 hPa in April) are favourable for occurrence of the squall over Delhi. The lower level inversion in March and April only also helps in the occurrence of squall. In monsoon months of July- September, cold and dry air advection in middle and upper tropospheric levels (8- 15° C below normal dew point at 400-300 hPa in July, about 15° C below normal dew point at 300-200 hPa in August and 17- 24° C below normal dew point at 500-300 hPa in September) favours occurrence of squall over Delhi. Unlike pre-monsoon months lower level moisture does not play any role for the occurrence of squall over Delhi in monsoon months. Significantly higher than normal SWEAT index in March to September at 0000 UTC can be used as predictor of squall over Delhi on that day. Total totals index is the next suitable precursor for all the months except June.

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