scholarly journals Comparing the cloud vertical structure derived from several methods based on radiosonde profiles and ground-based remote sensing measurements

2014 ◽  
Vol 7 (8) ◽  
pp. 2757-2773 ◽  
Author(s):  
M. Costa-Surós ◽  
J. Calbó ◽  
J. A. González ◽  
C. N. Long
Keyword(s):  
Remote Sensing ◽  
Vertical Structure ◽  
Cloud Layer ◽  
Cloud Base ◽  
Low Resolution ◽  
Telecommunication System ◽  
Perfect Agreement ◽  
Data Set ◽  
Global Telecommunication System ◽  
The Impact

Abstract. The cloud vertical distribution and especially the cloud base height, which is linked to cloud type, are important characteristics in order to describe the impact of clouds on climate. In this work, several methods for estimating the cloud vertical structure (CVS) based on atmospheric sounding profiles are compared, considering the number and position of cloud layers, with a ground-based system that is taken as a reference: the Active Remote Sensing of Clouds (ARSCL). All methods establish some conditions on the relative humidity, and differ in the use of other variables, the thresholds applied, or the vertical resolution of the profile. In this study, these methods are applied to 193 radiosonde profiles acquired at the Atmospheric Radiation Measurement (ARM) Southern Great Plains site during all seasons of the year 2009 and endorsed by Geostationary Operational Environmental Satellite (GOES) images, to confirm that the cloudiness conditions are homogeneous enough across their trajectory. The perfect agreement (i.e., when the whole CVS is estimated correctly) for the methods ranges between 26 and 64%; the methods show additional approximate agreement (i.e., when at least one cloud layer is assessed correctly) from 15 to 41%. Further tests and improvements are applied to one of these methods. In addition, we attempt to make this method suitable for low-resolution vertical profiles, like those from the outputs of reanalysis methods or from the World Meteorological Organization's (WMO) Global Telecommunication System. The perfect agreement, even when using low-resolution profiles, can be improved by up to 67% (plus 25% of the approximate agreement) if the thresholds for a moist layer to become a cloud layer are modified to minimize false negatives with the current data set, thus improving overall agreement.

scholarly journals Comparing the cloud vertical structure derived from several methods based on measured atmospheric profiles and active surface measurements

2014 ◽  
Vol 7 (4) ◽  
pp. 3681-3725
Author(s):  
M. Costa-Surós ◽  
J. Calbó ◽  
J. A. González ◽  
C. N. Long
Keyword(s):  
Vertical Structure ◽  
Current Data ◽  
Cloud Layer ◽  
Cloud Base ◽  
Low Resolution ◽  
Telecommunication System ◽  
Perfect Agreement ◽  
Data Set ◽  
Global Telecommunication System ◽  
The Impact

Abstract. The cloud vertical distribution and especially the cloud base height, which is linked to cloud type, is an important characteristic in order to describe the impact of clouds on climate. In this work several methods to estimate the cloud vertical structure (CVS) based on atmospheric sounding profiles are compared, considering number and position of cloud layers, with a ground based system which is taken as a reference: the Active Remote Sensing of Clouds (ARSCL). All methods establish some conditions on the relative humidity, and differ on the use of other variables, the thresholds applied, or the vertical resolution of the profile. In this study these methods are applied to 193 radiosonde profiles acquired at the ARM Southern Great Plains site during all seasons of year 2009 and endorsed by GOES images, to confirm that the cloudiness conditions are homogeneous enough across their trajectory. The perfect agreement (i.e. when the whole CVS is correctly estimated) for the methods ranges between 26–64%; the methods show additional approximate agreement (i.e. when at least one cloud layer is correctly assessed) from 15–41%. Further tests and improvements are applied on one of these methods. In addition, we attempt to make this method suitable for low resolution vertical profiles, like those from the outputs of reanalysis methods or from the WMO's Global Telecommunication System. The perfect agreement, even when using low resolution profiles, can be improved up to 67% (plus 25% of approximate agreement) if the thresholds for a moist layer to become a cloud layer are modified to minimize false negatives with the current data set, thus improving overall agreement.

scholarly journals Comparing the cloud vertical structure derived from several methods based on measured atmospheric profiles and active surface measurements

2013 ◽  
Vol 13 (6) ◽  
pp. 14405-14445 ◽  
Author(s):  
M. Costa-Surós ◽  
J. Calbó ◽  
J. A. González ◽  
C. N. Long
Keyword(s):  
Great Plains ◽  
Vertical Structure ◽  
Active Surface ◽  
Atmospheric Modeling ◽  
Current Data ◽  
Cloud Base ◽  
Low Resolution ◽  
Data Set ◽  
Surface Measurements ◽  
The Impact

Abstract. The cloud vertical distribution and especially the cloud base height, which is linked to cloud type, is an important characteristic in order to describe the impact of clouds in a changing climate. In this work several methods to estimate the cloud vertical structure (CVS) based on atmospheric sounding profiles are compared, considering number and position of cloud layers, with a ground based system which is taken as a reference: the Active Remote Sensing of Clouds (ARSCL). All methods establish some conditions on the relative humidity, and differ on the use of other variables, the thresholds applied, or the vertical resolution of the profile. In this study these methods are applied to 125 radiosonde profiles acquired at the ARM Southern Great Plains site during all seasons of year 2009 and endorsed by GOES images, to confirm that the cloudiness conditions are homogeneous enough across their trajectory. The overall agreement for the methods ranges between 44–88%; four methods produce total agreements around 85%. Further tests and improvements are applied on one of these methods. In addition, we attempt to make this method suitable for low resolution vertical profiles, which could be useful in atmospheric modeling. The total agreement, even when using low resolution profiles, can be improved up to 91% if the thresholds for a moist layer to become a cloud layer are modified to minimize false negatives with the current data set, thus improving overall agreement.

A Statistical Model of Cloud Vertical Structure Based on Reconciling Cloud Layer Amounts Inferred from Satellites and Radiosonde Humidity Profiles

2005 ◽  
Vol 18 (17) ◽  
pp. 3587-3605 ◽  
Author(s):  
William B. Rossow ◽  
Yuanchong Zhang ◽  
Junhong Wang
Keyword(s):  
Statistical Model ◽  
Vertical Structure ◽  
Atmospheric Temperature ◽  
Radiative Flux ◽  
Cloud Layer ◽  
Cloud Base ◽  
Polar Regions ◽  
Flux Divergence ◽  
Climate Scale ◽  
Humidity Profiles

Abstract To diagnose how cloud processes feed back on weather- and climate-scale variations of the atmosphere requires determining the changes that clouds produce in the atmospheric diabatic heating by radiation and precipitation at the same scales of variation. In particular, not only the magnitude of these changes must be quantified but also their correlation with atmospheric temperature variations; hence, the space–time resolution of the cloud perturbations must be sufficient to account for the majority of these variations. Although extensive new global cloud and radiative flux datasets have recently become available, the vertical profiles of clouds and consequent radiative flux divergence have not been systematically measured covering weather-scale variations from about 100 km, 3 h up to climate-scale variations of 10 000 km, decadal inclusive. By combining the statistics of cloud layer occurrence from the International Satellite Cloud Climatology Project (ISCCP) and an analysis of radiosonde humidity profiles, a statistical model has been developed that associates each cloud type, recognizable from satellite measurements, with a particular cloud vertical structure. Application of this model to the ISCCP cloud layer amounts produces estimates of low-level cloud amounts and average cloud-base pressures that are quantitatively closer to observations based on surface weather observations, capturing the variations with latitude and season and land and ocean (results are less good in the polar regions). The main advantage of this statistical model is that the correlations of cloud vertical structure with meteorology are qualitatively similar to “classical” information relating cloud properties to weather. These results can be evaluated and improved with the advent of satellites that can directly probe cloud vertical structures over the globe, providing statistics with changing meteorological conditions.

scholarly journals Assessing the impact of the Kuroshio Current on vertical cloud structure using CloudSat data

2018 ◽  
Vol 18 (10) ◽  
pp. 7657-7667 ◽  
Author(s):  
Akira Yamauchi ◽  
Kazuaki Kawamoto ◽  
Atsuyoshi Manda ◽  
Jiming Li
Keyword(s):  
Vertical Structure ◽  
Rainfall Intensity ◽  
Kuroshio Current ◽  
Cloud Layer ◽  
Frequency Of Occurrence ◽  
Surrounding Areas ◽  
The Impact ◽  
The Kuroshio ◽  
Precipitating Clouds ◽  
Geometric Thickness

Abstract. This study analyzed CloudSat satellite data to determine how the warm ocean Kuroshio Current affects the vertical structure of clouds. Rainfall intensity around the middle troposphere (6 km in height) over the Kuroshio was greater than that over surrounding areas. The drizzle clouds over the Kuroshio have a higher frequency of occurrence of geometrically thin (0.5–3 km) clouds and thicker (7–10 km) clouds compared to those around the Kuroshio. Moreover, the frequency of occurrence of precipitating clouds with a geometric thickness of 7 to 10 km increased over the Kuroshio. Stronger updrafts over the Kuroshio maintain large droplets higher in the upper part of the cloud layer, and the maximum radar reflectivity within a cloud layer in non-precipitating and drizzle clouds over the Kuroshio is higher than that around the Kuroshio.

scholarly journals Factors that influence surface PM<sub>2.5</sub> values inferred from satellite observations: perspective gained for the US Baltimore–Washington metropolitan area during DISCOVER-AQ

2014 ◽  
Vol 14 (4) ◽  
pp. 2139-2153 ◽  
Author(s):  
S. Crumeyrolle ◽  
G. Chen ◽  
L. Ziemba ◽  
A. Beyersdorf ◽  
L. Thornhill ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Metropolitan Area ◽  
Scattering Coefficient ◽  
Data Set ◽  
Ambient Relative Humidity ◽  
Microphysical Properties ◽  
The Us ◽  
Dry Conditions ◽  
The Impact

Abstract. During the NASA DISCOVER-AQ campaign over the US Baltimore, MD–Washington, D.C., metropolitan area in July 2011, the NASA P-3B aircraft performed extensive profiling of aerosol optical, chemical, and microphysical properties. These in situ profiles were coincident with ground-based remote sensing (AERONET) and in situ (PM2.5) measurements. Here, we use this data set to study the correlation between the PM2.5 observations at the surface and the column integrated measurements. Aerosol optical depth (AOD550 nm) calculated with the extinction (550 nm) measured during the in situ profiles was found to be strongly correlated with the volume of aerosols present in the boundary layer (BL). Despite the strong correlation, some variability remains, and we find that the presence of aerosol layers above the BL (in the buffer layer – BuL) introduces significant uncertainties in PM2.5 estimates based on column-integrated measurements (overestimation of PM2.5 by a factor of 5). This suggests that the use of active remote sensing techniques would dramatically improve air quality retrievals. Indeed, the relationship between the AOD550 nm and the PM2.5 is strongly improved by accounting for the aerosol present in and above the BL (i.e., integrating the aerosol loading from the surface to the top of the BuL). Since more than 15% of the AOD values observed during DISCOVER-AQ are dominated by aerosol water uptake, the f(RH)amb (ratio of scattering coefficient at ambient relative humidity (RH) to scattering coefficient at low RH; see Sect. 3.2) is used to study the impact of the aerosol hygroscopicity on the PM2.5 retrievals. The results indicate that PM2.5 can be predicted within a factor up to 2 even when the vertical variability of the f(RH)amb is assumed to be negligible. Moreover, f(RH = 80%) and RH measurements performed at the ground may be used to estimate the f(RH)amb during dry conditions (RHBL < 55%).

scholarly journals Global gridded precipitation over land: a description of the new GPCC First Guess Daily product

2014 ◽  
Vol 6 (1) ◽  
pp. 49-60 ◽  
Author(s):  
K. Schamm ◽  
M. Ziese ◽  
A. Becker ◽  
P. Finger ◽  
A. Meyer-Christoffer ◽  
...  
Keyword(s):  
Quality Control ◽  
Real Time ◽  
Daily Precipitation ◽  
Grid Cell ◽  
Rain Gauge ◽  
Kriging Interpolation ◽  
Telecommunication System ◽  
Full Data ◽  
Data Set ◽  
Global Telecommunication System

Abstract. This paper describes the new First Guess Daily product of the Global Precipitation Climatology Centre (GPCC). The new product gives an estimate of the global daily precipitation gridded at a spatial resolution of 1° latitude by 1° longitude. It is based on rain gauge data reported in near-real time via the Global Telecommunication System (GTS) and available about three to five days after the end of each observation month. In addition to the gridded daily precipitation totals in mm day−1, the standard deviation in mm day−1, the kriging interpolation error in % and the number of measurements per grid cell are also encoded into the monthly netCDF product file and provided for all months since January 2009. Prior to their interpolation, the measured precipitation values undergo a preliminary automatic quality control. For the calculation of the areal mean of the grid, anomalies are interpolated with ordinary block kriging. This approach allows for a near-real-time release. Therefore, the purely GTS-based data processing lacks an intensive quality control as well as a high data density and is denoted as First Guess. The daily data set is referenced under doi:10.5676/DWD_GPCC/FG_D_100. Two further products, the Full Data Daily and a merged satellite-gauge product, are currently under development at Deutscher Wetterdienst (DWD). These additional products will not be available in near-real time, but based on significantly more and strictly quality controlled observations. All GPCC products are provided free of charge via the GPCC webpage: ftp://ftp-anon.dwd.de/pub/data/gpcc/html/download_gate.html.

The 2009 Wesley impact: Asteroidal or Cometary?

2021 ◽  
Author(s):  
James Sinclair ◽  
Glenn Orton ◽  
Meera Krishnamoorty ◽  
Leigh Fletcher ◽  
Joseph Hora ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Radiative Transfer ◽  
Heterogeneous Population ◽  
Atmospheric Response ◽  
Atmospheric Models ◽  
Low Resolution ◽  
Impact Site ◽  
Long Time ◽  
The Impact ◽  
Unknown Object

&lt;p&gt;We present Earth-based observations of Jupiter from 1994 and 2009, which respectively capture the effects on Jupiter&amp;#8217;s atmosphere by the impacts of Comet D/Shoemaker-Levy 9 (SL9) and the impact by an unknown object whose visible impression on Jupiter&amp;#8217;s appearance was discovered by Anthony Wesley.&amp;#160; Previous studies have suggested the 2009 impactor was by an asteroid on the basis of differences in Jupiter&amp;#8217;s atmospheric response compared to the 1994 impact by SL9.&amp;#160; These differences include detections of 9.1-&amp;#956;m silicate features in the 2009 impact site (Orton et al., 2010, Icarus 211, 587-602) and the fact the 2009 debris field shrank faster (Hammel et al., 2010, ApJL 715, L150-L154), both of which suggest the 2009 impactor was more rocky/refractory in composition.&amp;#160; However, Schenk &lt;em&gt;et al.&lt;/em&gt; 2004 (Jupiter: The Planet, Satellites and Magnetosphere, Bagenal, Dowling, McKinnon, 427-456) state that comets are orders of magnitude more likely to impact Jupiter than asteroids since Jupiter should have cleared its orbit a long time ago. Thus, either (1) the 2009 impact was caused by an asteroid and therefore a statistical fluke, (2) Jupiter-Family Comets (JFCs) are a highly heterogeneous population, with some containing rocky/refractory interiors hidden from remote-sensing, or (3) there is a population of asteroids among bodies classified as JFCs. In order to explore these hypotheses, we performed a comparative spectral re-analysis of broadband imaging and low-resolution spectra measured during/after the 1994 and 2009 impacts. The comparison used consistent procedures for reduction and calibration of the data, atmospheric models, radiative-transfer software and spectroscopic line data in order to facilitate direct comparisons between 1994 and 2009 events. &amp;#160;&lt;/p&gt;

scholarly journals J-PAS : Low-resolution (R ∼ 50) spectroscopy covering 8000 deg2

2014 ◽  
Vol 10 (S309) ◽  
pp. 29-30
Author(s):  
C. López-Sanjuan ◽  
A. J. Cenarro ◽  
L. A. Díaz-García ◽  
D. J. Muniesa ◽  
I. San Roman ◽  
...  
Keyword(s):  
Star Formation Rate ◽  
Formation Rate ◽  
Elliptical Galaxies ◽  
3D Analysis ◽  
Low Resolution ◽  
Local Universe ◽  
Photometric Redshifts ◽  
Data Set ◽  
Nearby Galaxies ◽  
The Impact

AbstractWe present the ambitious project J-PAS, that will cover 8000 deg2 of the northern sky with 54 narrow-band (∼145Å) contiguous filters, all of them in the optical range (3700Å-9200Å). J-PAS will provide a low resolution spectra (R ∼ 50) in every pixel of the northern sky by 2020, leading to excellent photometric redshifts (0.3% uncertainty) of 100 million sources. J-PAS will permit the study of the 2D properties of nearby galaxies with unprecedented statistics. Some viable studies are the distribution of the star formation rate traced by Hα, the stellar populations gradients in elliptical galaxies up to a few effective radii, or the impact of environment in galaxy properties. In summary, J-PAS will bring a superb data set for 3D analysis in the local Universe.

scholarly journals Synergistic use of Lagrangian dispersion and radiative transfer modelling with satellite and surface remote sensing measurements for the investigation of volcanic plumes: the Mount Etna eruption of 25–27 October 2013

2016 ◽  
Vol 16 (11) ◽  
pp. 6841-6861 ◽  
Author(s):  
Pasquale Sellitto ◽  
Alcide di Sarra ◽  
Stefano Corradini ◽  
Marie Boichu ◽  
Hervé Herbin ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Size Distribution ◽  
Volcanic Eruption ◽  
Radiative Forcing ◽  
Mount Etna ◽  
Aerosol Size Distribution ◽  
Volcanic Plume ◽  
Data Set ◽  
Lagrangian Dispersion ◽  
The Impact

Abstract. In this paper we combine SO2 and ash plume dispersion modelling with satellite and surface remote sensing observations to study the regional influence of a relatively weak volcanic eruption from Mount Etna on the optical and micro-physical properties of Mediterranean aerosols. We analyse the Mount Etna eruption episode of 25–27 October 2013. The evolution of the plume along the trajectory is investigated by means of the FLEXible PARTicle Lagrangian dispersion (FLEXPART) model. The satellite data set includes true colour images, retrieved values of volcanic SO2 and ash, estimates of SO2 and ash emission rates derived from MODIS (MODerate resolution Imaging Spectroradiometer) observations and estimates of cloud top pressure from SEVIRI (Spinning Enhanced Visible and InfraRed Imager). Surface remote sensing measurements of aerosol and SO2 made at the ENEA Station for Climate Observations (35.52° N, 12.63° E; 50 m a.s.l.) on the island of Lampedusa are used in the analysis. The combination of these different data sets suggests that SO2 and ash, despite the initial injection at about 7.0 km altitude, reached altitudes around 10–12 km and influenced the column average aerosol particle size distribution at a distance of more than 350 km downwind. This study indicates that even a relatively weak volcanic eruption may produce an observable effect on the aerosol properties at the regional scale. The impact of secondary sulfate particles on the aerosol size distribution at Lampedusa is discussed and estimates of the clear-sky direct aerosol radiative forcing are derived. Daily shortwave radiative forcing efficiencies, i.e. radiative forcing per unit AOD (aerosol optical depth), are calculated with the LibRadtran model. They are estimated between −39 and −48 W m−2 AOD−1 at the top of the atmosphere and between −66 and −49 W m−2 AOD−1 at the surface, with the variability in the estimates mainly depending on the aerosol single scattering albedo. These results suggest that sulfate particles played a large role in the transported plume composition and radiative forcing, while the contribution by ash particles was small in the volcanic plume arriving at Lampedusa during this event.

scholarly journals Improved Prediction of Bay of Bengal Tropical Cyclones through Assimilation of Doppler Weather Radar Observations

2015 ◽  
Vol 143 (11) ◽  
pp. 4533-4560 ◽  
Author(s):  
Krishna K. Osuri ◽  
U. C. Mohanty ◽  
A. Routray ◽  
Dev Niyogi
Keyword(s):  
Bay Of Bengal ◽  
Inner Core ◽  
Weather Radar ◽  
Doppler Weather Radar ◽  
Telecommunication System ◽  
Rainfall Prediction ◽  
Warm Core ◽  
Global Telecommunication System ◽  
The Impact ◽  
Ice Phase

Abstract The impact on tropical cyclone (TC) prediction from assimilating Doppler weather radar (DWR) observations obtained from the TC inner core and environment over the Bay of Bengal (BoB) is studied. A set of three operationally relevant numerical experiments were conducted for 24 forecast cases involving 5 unique severe/very severe BoB cyclones: Sidr (2007), Aila (2009), Laila (2010), Jal (2010), and Thane (2011). The first experiment (CNTL) used the NCEP FNL analyses for model initial and boundary conditions. In the second experiment [Global Telecommunication System (GTS)], the GTS observations were assimilated into the model initial condition while the third experiment (DWR) used DWR with GTS observations. Assimilation of the TC environment from DWR improved track prediction by 32%–53% for the 12–72-h forecast over the CNTL run and by 5%–25% over GTS and was consistently skillful. More gains were seen in intensity, track, and structure by assimilating inner-core DWR observations as they provided more realistic initial organization/asymmetry and strength of the TC vortex. Additional experiments were conducted to assess the role of warm-rain and ice-phase microphysics to assimilate DWR reflectivity observations. Results indicate that the ice-phase microphysics has a dominant impact on inner-core reflectivity assimilation and in modifying the intensity evolution, hydrometeors, and warm core structure, leading to improved rainfall prediction. This study helps provide a baseline for the credibility of an observational network and assist with the transfer of research to operations over the India monsoon region.

Sign in / Sign up

Export Citation Format

Share Document