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 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

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 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.

scholarly journals Impact of gold and oil prices on the stock market in Pakistan

2020 ◽  
Vol 25 (50) ◽  
pp. 279-294
Author(s):  
Aiza Shabbir ◽  
Shazia Kousar ◽  
Syeda Azra Batool
Keyword(s):  
Stock Market ◽  
Stock Returns ◽  
Stock Exchange ◽  
Structural Break ◽  
Oil Prices ◽  
Current Data ◽  
Small Sample ◽  
Data Set ◽  
Content Type ◽  
The Impact

Purpose The purpose of the study is to find out the impact of gold and oil prices on the stock market. Design/methodology/approach This study uses the data on gold prices, stock exchange and oil prices for the period 1991–2016. This study applied descriptive statistics, augmented Dickey–Fuller test, correlation and autoregressive distributed lag test. Findings The data analysis results showed that gold and oil prices have a significant impact on the stock market. Research limitations/implications Following empirical evidence of this study, the authors recommend that investors should invest in gold because the main reason is that hike in inflation reduces the real value of money, and people seek to invest in alternative investment avenues like gold to preserve the value of their assets and earn additional returns. This suggests that investment in gold can be used as a tool to decline inflation pressure to a sustainable level. This study was restricted to use small sample data owing to the availability of data from 1991 to 2017 and could not use structural break unit root tests with two structural break and structural break cointegration approach, as these tests require high-frequency data set. Originality/value This study provides information to the investors who want to get the benefit of diversification by investing in gold, oil and stock market. In the current era, gold prices and oil prices are fluctuating day by day, and investors think that stock returns may or may not be affected by these fluctuations. This study is unique because it focusses on current issues and takes the current data in this research to help investment institutions or portfolio managers.

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 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.

scholarly journals Radiation transfer in stratus clouds at the BSRN Payerne site

2008 ◽  
Vol 8 (3) ◽  
pp. 11453-11485 ◽  
Author(s):  
D. Nowak ◽  
L. Vuilleumier ◽  
A. Ohmura
Keyword(s):  
Radiation Transfer ◽  
Radiant Energy ◽  
Cloud Layer ◽  
Surface Energy Budget ◽  
Surface Radiation ◽  
Set Covering ◽  
Cloud Base ◽  
Data Set ◽  
Stratus Cloud ◽  
Radiation Fluxes

Abstract. Clouds represent a major source of uncertainty in understanding climate change, because potential changes in the way they affect the atmospheric and surface energy budget are difficult to predict. It is therefore important to determine how clouds affect radiation. Stratiform clouds in particular have an important effect on climate as they cover large areas. This article presents results of radiation transfer calculations with MODTRANTM for well-defined stratus cloud cases detected at the meteorological station of Payerne, Switzerland. These stratus situations are selected in a data set covering the years from 2000 to 2005 with a method using data widely available at national meteorological observing stations. For 18 single layer stratus situations the shortwave radiation fluxes calculated with MODTRANTM are compared to surface observations from the Baseline Surface Radiation Network (BSRN) site at Payerne and top of atmosphere (TOA) observations from the Clouds and the Earth's Radiant Energy System (CERES) experiment. A median bias on the order of 20 Wm−2 (<9%) was found for the differences between modeled and observed reflected solar radiation at TOA. At the surface, good agreement is obtained by adjusting the vertical extinction in the modeled cloud layer within reasonable limits for a stratus cloud: The median bias of modeled minus observed shortwave downward radiation is well within instrument precision (<1%). The simultaneous agreement of modeled and observed radiation fluxes at the surface and TOA confirmed that radiation transfer in the atmosphere including a single cloud layer can be well simulated with MODTRANTM. Based on the present results, the absorbance was calculated within the stratus cloud layer (cloud base to cloud top). For the 18 single stratus layer situations the median absorbance is 0.07 [minimum 0.04, maximum 0.1], the median transmittance is 0.29 [0.15 0.39], and the median cloud reflectance is 0.70 [0.63, 0.80].

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

2018 ◽  
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 analysed 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 updraft over the Kuroshio maintains 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.

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