scholarly journals Supplementary material to "Linear relationship between effective radius and precipitation water content near the top of convective clouds"

2021 ◽  
Author(s):  
Ramon Campos Braga ◽  
Daniel Rosenfeld ◽  
Ovid O. Krüger ◽  
Barbara Ervens ◽  
Bruna A. Holanda ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Water Content ◽  
Effective Radius ◽  
Convective Clouds ◽  
Precipitation Water ◽  
Supplementary Material

scholarly journals Linear relationship between effective radius and precipitation water content near the top of convective clouds

2021 ◽  
Author(s):  
Ramon Campos Braga ◽  
Daniel Rosenfeld ◽  
Ovid O. Krüger ◽  
Barbara Ervens ◽  
Bruna A. Holanda ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Water Content ◽  
Amazon Basin ◽  
Hydrological Cycle ◽  
Cloud Condensation Nuclei ◽  
Effective Radius ◽  
Convective Clouds ◽  
Warm Rain ◽  
Precipitation Water ◽  
Cloud Tops

Abstract. Quantifying the precipitation within clouds is a crucial challenge to improve our current understanding of the Earth’s hydrological cycle. We have investigated the relationship between the effective radius of droplets and ice particles (re) and precipitation water content (PWC) measured by cloud probes near the top of growing convective cumuli. The data for this study were collected by aircraft measurements in clean and polluted conditions over the Amazon Basin and over the western tropical Atlantic in September 2014. Our results indicate a threshold of re ∼ 13 μm for warm rain initiation in convective clouds, which is in agreement with previous studies. In clouds over the Atlantic Ocean, warm rain starts at smaller re, likely linked to the enhancement of coalescence of drops formed on giant cloud condensation nuclei. In cloud passes where precipitation starts as ice hydrometeors, the threshold of re is also shifted to values smaller than 13 μm when coalescence processes are suppressed and precipitating particles are formed by accretion. We found a statistically significant linear relationship between PWC and re for measurements at cloud tops, with a correlation coefficient of ∼0.94. The tight relationship between re and PWC was established only when particles with sizes large enough to precipitate (drizzle and raindrops) are included in calculating re. Our results emphasize for the first time that re is a key parameter to determine both initiation and amount of precipitation at the top of convective clouds.

scholarly journals Linear relationship between effective radius and precipitation water content near the top of convective clouds: measurement results from ACRIDICON–CHUVA campaign

2021 ◽  
Vol 21 (18) ◽  
pp. 14079-14088
Author(s):  
Ramon Campos Braga ◽  
Daniel Rosenfeld ◽  
Ovid O. Krüger ◽  
Barbara Ervens ◽  
Bruna A. Holanda ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Water Content ◽  
Amazon Basin ◽  
Hydrological Cycle ◽  
Cloud Condensation Nuclei ◽  
Effective Radius ◽  
Convective Clouds ◽  
Warm Rain ◽  
Precipitation Water ◽  
Cloud Tops

Abstract. Quantifying the precipitation within clouds is a crucial challenge to improve our current understanding of the Earth's hydrological cycle. We have investigated the relationship between the effective radius of droplets and ice particles (re) and precipitation water content (PWC) measured by cloud probes near the top of growing convective cumuli. The data for this study were collected during the ACRIDICON–CHUVA campaign on the HALO research aircraft in clean and polluted conditions over the Amazon Basin and over the western tropical Atlantic in September 2014. Our results indicate a threshold of re∼13 µm for warm rain initiation in convective clouds, which is in agreement with previous studies. In clouds over the Atlantic Ocean, warm rain starts at smaller re, likely linked to the enhancement of coalescence of drops formed on giant cloud condensation nuclei. In cloud passes where precipitation starts as ice hydrometeors, the threshold of re is also shifted to values smaller than 13 µm when coalescence processes are suppressed and precipitating particles are formed by accretion. We found a statistically significant linear relationship between PWC and re for measurements at cloud tops, with a correlation coefficient of ∼0.94. The tight relationship between re and PWC was established only when particles with sizes large enough to precipitate (drizzle and raindrops) are included in calculating re. Our results emphasize for the first time that re is a key parameter to determine both initiation and amount of precipitation at the top of convective clouds.

Inferring the effects of surface canopy water on VOD estimation from L-band backscatter 

2021 ◽  
Author(s):  
Saeed Khabbazan ◽  
Paul.C. Vermunt ◽  
Susan.C. Steele Dunne ◽  
Ge Gao ◽  
Mariette Vreugdenhil ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Linear Relationship ◽  
Water Content ◽  
Growing Season ◽  
Empirical Parameter ◽  
Vegetation Water Content ◽  
L Band ◽  
Vegetation Water ◽  
Canopy Water ◽  
Effect Of Surface

<p>Quantification of vegetation parameters such as Vegetation Optical Depth (VOD) and Vegetation Water Content (VWC) can be used for better irrigation management, yield forecasting, and soil moisture estimation. Since VOD is directly related to vegetation water content and canopy structure, it can be used as an indicator for VWC. Over the past few decades, optical and passive microwave satellite data have mostly been used to monitor VWC. However, recent research is using active data to monitor VOD and VWC benefitting from their high spatial and temporal resolution.</p><p>Attenuation of the microwave signal through the vegetation layer is parametrized by the VOD. VOD is assumed to be linearly related to VWC with the proportionality constant being an empirical parameter b. For a given wavelength and polarization, b is assumed static and only parametrized as a function of vegetation type. The hypothesis of this study is that the VOD is not similar for dry and wet vegetation and the static linear relationship between attenuation and vegetation water content is a simplification of reality.</p><p>The aim of this research is to understand the effect of surface canopy water on VOD estimation and the relationship between VOD and vegetation water content during the growing season of a corn canopy. In addition to studying the dependence of VOD on bulk VWC for dry and wet vegetation, the effect of different factors, such as different growth stages and internal vegetation water content is investigated using time series analysis.</p><p>A field experiment was conducted in Florida, USA, for a full growing season of sweet corn. The corn field was scanned every 30 minutes with a truck-mounted, fully polarimetric, L-band radar. Pre-dawn vegetation water content was measured using destructive sampling three times a week for a full growing season. VWC could therefore be analyzed by constituent (leaf, stem, ear) or by height. Meteorological data, surface canopy water (dew or interception), and soil moisture were measured every 15 minutes for the entire growing season.</p><p>The methodology of Vreugdenhil et al.  [1], developed by TU Wien for ASCAT data, was adapted to present a new technique to estimate VOD from single-incidence angle backscatter data in each polarization. The results showed that the effect of surface canopy water on the VOD estimation increased by vegetation biomass accumulation and the effect was higher in the VOD estimated from the co-pol compared with the VOD estimated from the cross-pol. Moreover, the surface canopy water considerably affected the regression coefficient values (b-factor) of the linear relationship between VOD and VWC from dry and wet vegetation. This finding suggests that considering a similar b-factor for the dry and the wet vegetation will introduce errors in soil moisture retrievals. Furthermore, it highlights the importance of considering canopy wetness conditions when using tau-omega.</p><ul><li>[1] Vreugdenhil,W. A. Dorigo,W.Wagner, R. A. De Jeu, S. Hahn, andM. J. VanMarle, “Analyzing the vegetation parameterization in the TU-Wien ASCAT soil moisture retrieval,” IEEE Transactions on Geoscience and Remote Sensing, vol. 54, pp. 3513–3531, 2016</li> </ul>

Effect of acute edema on left ventricular function and coronary vascular resistance in the isolated rat heart

1994 ◽  
Vol 267 (3) ◽  
pp. H1054-H1061 ◽  
Author(s):  
A. Rubboli ◽  
P. A. Sobotka ◽  
D. E. Euler
Keyword(s):  
Linear Relationship ◽  
Water Content ◽  
Vascular Resistance ◽  
Diastolic Pressure ◽  
Myocardial Edema ◽  
Left Ventricular ◽  
Coronary Vascular Resistance ◽  
Ventricular Performance ◽  
Developed Pressure ◽  
The Impact

The impact of acute myocardial edema on coronary flow and left ventricular performance was studied in isolated isovolumic rat hearts. After 15 min of aortic perfusion with Krebs-Henseleit buffer, hearts (10/group) were either removed for determination of water content or perfused for another 90 min. Three groups were perfused at a constant pressure of 60, 100, or 140 mmHg, and two groups were perfused at 60 or 140 mmHg with adenosine added. Compared with the 15-min group, there was a significant increase in water content in all groups except the 60-mmHg group (P < 0.005). There was a direct linear relationship between increases in coronary vascular resistance over time and water content (P < 0.0001). A decrease in developed pressure and peak +dP/dt was observed only in those groups that accumulated water. An inverse linear relationship was found between changes in developed pressure and water content (P = 0.0001). Water content had no effect on end-diastolic pressure below 5 ml/g; above 5 ml/g, a direct linear relationship was evident (P = 0.009). The results suggest that myocardial edema increases vascular resistance and decreases systolic performance. End-diastolic pressure is less influenced by edema than either systolic or coronary vascular function.

Observed Southern Ocean Cloud Properties and Shortwave Reflection. Part I: Calculation of SW Flux from Observed Cloud Properties*

2014 ◽  
Vol 27 (23) ◽  
pp. 8836-8857 ◽  
Author(s):  
Daniel T. McCoy ◽  
Dennis L. Hartmann ◽  
Daniel P. Grosvenor
Keyword(s):  
Seasonal Variation ◽  
Solar Radiation ◽  
Southern Ocean ◽  
Water Content ◽  
Liquid Water ◽  
Effective Radius ◽  
Shortwave Radiation ◽  
Liquid Water Path ◽  
Cloud Liquid Water ◽  
Cloud Properties

Abstract The sensitivity of the reflection of shortwave radiation over the Southern Ocean to the cloud properties there is estimated using observations from a suite of passive and active satellite instruments in combination with radiative transfer modeling. A composite cloud property observational data description is constructed that consistently incorporates mean cloud liquid water content, ice water content, liquid and ice particle radius information, vertical structure, vertical overlap, and spatial aggregation of cloud water as measured by optical depth versus cloud-top pressure histograms. The observational datasets used are Moderate Resolution Imaging Spectroradiometer (MODIS) effective radius filtered to mitigate solar zenith angle bias, the Multiangle Imaging Spectroradiometer (MISR) cloud-top height–optical depth (CTH–OD) histogram, the liquid water path from the University of Wisconsin dataset, and ice cloud properties from CloudSat. This cloud database is used to compute reflected shortwave radiation as a function of month and location over the ocean from 40° to 60°S, which compares well with observations of reflected shortwave radiation. This calculation is then used to test the sensitivity of the seasonal variation of shortwave reflection to the observed seasonal variation of cloud properties. Effective radius decreases during the summer season, which results in an increase in reflected solar radiation of 4–8 W m−2 during summer compared to what would be reflected if the effective radius remained constant at its annual-mean value. Summertime increases in low cloud fraction similarly increase the summertime reflection of solar radiation by 9–11 W m−2. In-cloud liquid water path is less in summertime, causing the reflected solar radiation to be 1–4 W m−2 less.

Complexation of the La(III) cation by p-sulfonatocalix[4]arene — A 139La NMR study

2002 ◽  
Vol 80 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Yaël Israëli ◽  
Christine Bonal ◽  
Christian Detellier ◽  
Jean-Pierre Morel ◽  
Nicole Morel-Desrosiers
Keyword(s):  
Linear Relationship ◽  
Standard Enthalpy ◽  
Effective Radius ◽  
Water Soluble ◽  
Water Molecules ◽  
Standard Entropy ◽  
Nmr Data ◽  
Nmr Study ◽  
Good Agreement ◽  
Formation Of Complexes

The complexation of La(III) by the water-soluble p-sulfonatocalix[4]arene was thermodynamically characterized by 139La NMR. The 139La NMR data are consistent with the formation of a 1:1 complex resulting from electro static interactions between the sulfonato groups and La(III). The complexation is entropy-driven and is characterized by a positive standard enthalpy (ΔrH° = 11.0 ± 0.5 kJ mol–1) and a positive standard entropy (ΔrS° = 108 ± 2 J K–1 mol–1), which are in very good agreement with the ones determined previously by microcalorimetry. The linear relationship between the 139La NMR linewidth of the free and of the complexed cation, obtained at temperatures ranging from 290 to 340 K, excludes the formation of complexes or aggregates other than the 1:1 complex. It shows also that upon complexation, the effective radius of La(III) undergoes an increase of 50%, related to the replacement of water molecules of the hydrated cation by sulfonato groups of the ligand.Key words: complexation, water-soluble calixarene, p-sulfonatocalix[4]arene, 139La NMR, lanthanum.

scholarly journals Effective Radius of Ice Particles in Cirrus and Contrails

2011 ◽  
Vol 68 (2) ◽  
pp. 300-321 ◽  
Author(s):  
U. Schumann ◽  
B. Mayer ◽  
K. Gierens ◽  
S. Unterstrasser ◽  
P. Jessberger ◽  
...  
Keyword(s):  
Water Content ◽  
Effective Radius ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Small Particles ◽  
Particle Volume ◽  
Cross Sectional ◽  
Ice Particles ◽  
Ice Water Content ◽  
Ice Water

Abstract This paper discusses the ratio C between the volume mean radius and the effective radius of ice particles in cirrus and contrails. The volume mean radius is proportional to the third root of the ratio between ice water content and number of ice particles, and the effective radius measures the ratio between ice particle volume and projected cross-sectional area. For given ice water content and number concentration of ice particles, the optical depth scales linearly with C. Hence, C is an important input parameter for radiative forcing estimates. The ratio C in general depends strongly on the particle size distribution (PSD) and on the particle habits. For constant habits, C can be factored into a PSD and a habit factor. The PSD factor is generally less than one, while the habit factor is larger than one for convex or concave ice particles with random orientation. The value of C may get very small for power-law PSDs with exponent n between −4 and 0, which is often observed. For such PSDs, most of the particle volume is controlled by a few large particles, while most of the cross-sectional area is controlled by the many small particles. A new particle habit mix for contrail cirrus including small droxtal-shape particles is suggested. For measured cirrus and contrails, the dependence of C on volume mean particle radius, ambient humidity, and contrail age is determined. For cirrus, C varies typically between 0.4 and 1.1. In contrails, C = 0.7 ± 0.3, with uncertainty ranges increasing with the volume radius and contrail age. For the small particles in young contrails, the extinction efficiency in the solar range deviates considerably from the geometric optics limit.

scholarly journals Physical Properties of High-Level Cloud over Land and Ocean from CloudSat–CALIPSO Data

2014 ◽  
Vol 27 (23) ◽  
pp. 8966-8978 ◽  
Author(s):  
Juan Huo ◽  
Daren Lu
Keyword(s):  
Linear Relationship ◽  
Water Content ◽  
Northern China ◽  
Occurrence Frequency ◽  
Radiative Energy ◽  
Cloud Base ◽  
The Pacific ◽  
Ice Water Content ◽  
High Level ◽  
Ice Water

Abstract Unlike other cloud types, high-level clouds play an important role, often imposing a warming effect, in the earth–atmosphere radiative energy budget. In this paper, macro- and microphysical characteristics of cirrus clouds, such as their occurrence frequency, geometric scale, water content, and particle size, over northern China (land area, herein called the L area) and the Pacific Ocean (ocean area, herein the O area) are analyzed and compared based on CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) products from 1 January 2007 to 31 December 2010. Over both areas, statistical analysis shows that cirrus occurrence approached 33% in summer whereas it was only ~10% in winter, &gt;50% of cirrus cloud thicknesses were in the range of ~(0.25–1.5) km, there were &gt;98% ice particles in high-level clouds, and temperature had a closer linear relationship with ice effective radius (IER) than height. Also, the seasonal difference of this linear relationship is minor over both land and ocean. Comparisons reveal that the mean occurrence frequency, mean cloud thickness, range of cloud-base and cloud-top height, IER, and ice water content of cirrus in summer were generally greater in winter, and greater over the O area than over the L area. However, the relationship between IER and temperature over land is close to that over ocean.

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