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Overfishing of Inland Waters
2005
BioScience
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DAVID ALLAN, ROBIN ABELL, ZEB HOGAN, CARMEN REVENGA, BRAD W. TAYLOR, ROBIN L. ...
J. ...
doi:10.1641/0006-3568(2005)055[1041:ooiw]2.0.co;2
fatcat:5df6ll5kd5bmxffryryhhay6wi
Fast approximate calculation of multiply scattered lidar returns
2006
Applied Optics
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and P j s j in memory such that the weighted summations become ͑P j s 2 j ͒ ← ͑P j s 2 j ͒ ϩ ⌬P j ϫ ⌬s 2 j , (26) and similarly for P j 2 j and P j s j . ...
2 ϭ x i 2 ϩ ͑ x,i 2 ϩ x,i 2 ͒͑r j Ϫ r i͒ 2 ϩ 2x i x,i͑ r j Ϫ r i͒ , (20) ⌬P s,j ϭ ␣ i ⌬r, (21) ⌬s 2 s,j ϭ l 2 r j 2 ϩ ⌰ i 2 ͑ r j Ϫ r i͒ 2 , (22) ⌬ 2 s,j ϭ l 2 ϩ ⌰ i 2 , (23) ⌬s s,j ϭ l 2 r j ϩ ⌰ i 2 ͑ ...
doi:10.1364/ao.45.005984
pmid:16926887
fatcat:cn2ippewr5cldjyqyibyju6joy
Verification of cloud-fraction forecasts
2009
Quarterly Journal of the Royal Meteorological Society
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J. HOGAN ET AL. ...
J. ...
doi:10.1002/qj.481
fatcat:uffbyrsj7fdozlwwm562bpyr3q
Asperitas - a newly identified cloud supplementary feature
2017
Weather
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Cloud images obtained through a crowd-sourced international observing network suggest a cloud variety that has hitherto not been explicitly classified. This cloud feature shows a roughened base, which, under some solar illumination conditions, provides a particularly dramatic appearance. The growing body of photographic observations have led the World Meteorological Organisation to consider adding 'asperitas' to the 2017 edition of the International Cloud Atlas as a new form of supplementary
doi:10.1002/wea.2996
fatcat:nnqm66xdwfgq7atv2q5rjszj2m
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... ud feature. We compare reported sightings with available meteorological data to investigate the conditions that give rise to this newly recognised cloud description. 1 Cirrus dominated by irregularly curved filaments of ice, giving an entangled appearance. 2 from the Latin noun meaning roughness
Rainfall nowcasting by combining radars, microwave links and rain gauges
[article]
2018
arXiv
pre-print
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A similar assumption for radar observations has been made by Hogan (2007) . ...
The first quadrant of the covariance matrix of the state is given by B ij = B ii exp − d ij d 0 , (9) where B ii is the radar error and d ij is the distance between the pixel i and j, with i, j = 1, .. ...
arXiv:1810.11811v1
fatcat:sukzhsipc5bdfjmtzyy4odvxci
Copula-based synthetic data augmentation for machine- learning emulators
2021
Geoscientific Model Development
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., 2021; Hogan and Matricardi, 2020) . ...
For τ g we use a constant value of 1.7 determined by minimizing the absolute error between profiles computed with this simple model and the comprehensive atmospheric radiation scheme ecRad (Hogan and ...
doi:10.5194/gmd-14-5205-2021
fatcat:at6fzn7ijrfnrh27kuiwexgr6a
The Capacitance of Pristine Ice Crystals and Aggregate Snowflakes
2008
Journal of the Atmospheric Sciences
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Forbes and Hogan 2006) .
Method The simplest Monte Carlo model for solving (1) runs as follows. A random walker is placed on a large sphere, radius R ∞ . ...
doi:10.1175/2007jas2315.1
fatcat:372lp6jzn5dbtk67tlrfdwhsci
Stratocumulus Liquid Water Content from Dual-Wavelength Radar
2005
Journal of Atmospheric and Oceanic Technology
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A technique is described to retrieve stratocumulus liquid water content (LWC) using the differential attenuation measured by vertically pointing radars at 35 GHz and 94 GHz. Millimeter-wave attenuation is proportional to LWC and increases with frequency, so LWC can be derived without the need to make any assumptions on the nature of the droplet size distribution. There is also no need for the radars to be well calibrated. A significant advantage over many radar techniques in stratocumulus is
doi:10.1175/jtech1768.1
fatcat:lbe72kzbzzcrhk3j2qg2lks2sq
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... t the presence of drizzle drops (those with a diameter larger than around 50 µm) does not affect the retrieval, even though such drops may dominate the radar signal. It is important, however, that there are not significant numbers of drops larger than 600 µm which scatter outside the Rayleigh regime at 94 GHz. We use a lidar ceilometer to locate cloud base in the presence of drizzle falling below the cloud. An accuracy of around 0.04 g m −3 is achievable with averaging over one minute and 150 m (two range gates), but for the previously suggested frequency pair 10 GHz and 35 GHz, the corresponding accuracy would be considerably worse at 0.34 g m −3 . We first simulate the retrieval of LWC using aircraft-measured size spectra taken from a profile through marine stratocumulus. Results are then presented from two case studies, one using two cloud radars at Chilbolton in Southern England, and another using the Cloud Profiling Radar System at the Atmospheric Radiation Measurement site in Oklahoma. Liquid water path from the technique was found to be in good agreement with the values obtained from microwave radiometers, with the difference between the two being close to the accuracy of the radiometer retrieval. In the case of wellmixed stratocumulus the profiles were close to adiabatic.
Fast Reverse-Mode Automatic Differentiation using Expression Templates in C++
2014
ACM Transactions on Mathematical Software
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ACM Reference Format: Robin J. Hogan. 2014. Fast reverse-mode automatic differentiation using expression templates in C++. ACM ...
These methods make repeated estimates of x, at which they require not only the value of J but also the vector of gradients ∂ J/∂x in order to know in which direction to search next. ...
The third algorithm uses the Photon Variance-Covariance (PVC) method of Hogan [2008] and computes the contribution to the measured signal from light that has been scattered multiple times, but only by ...
doi:10.1145/2560359
fatcat:x7miqimrq5deta45vmfwdvtkqm
Combined CloudSat-CALIPSO-MODIS retrievals of the properties of ice clouds
2010
Journal of Geophysical Research
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(d, g, and j) The effect of assimilating the infrared radiances at 10 mm and the difference in radiance between 8 mm and 12 mm when S is assumed constant. ...
Stein et al., A comparison between different retrieval methods for ice cloud properties using data from the CloudSat and A-Train satellites, manuscript in preparation, 2010; J. ...
doi:10.1029/2009jd012346
fatcat:kswytxda3zbk7e7z5d4o7ukqai
Comparison of ECMWF Winter-Season Cloud Fraction with Radar-Derived Values
2001
Journal of applied meteorology (1988)
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The same dataset was used by Hogan and Illingworth (2000) to characterize the degree of cloud overlap for use in GCMs. ...
From around 14 hours of in situ aircraft measurements in mid-latitude cirrus, Hogan and Illingworth (1999b) derived the following relationship between 94-GHz radar reflectivity (Z 94 ) and IWC: log 10 ...
doi:10.1175/1520-0450(2001)040<0513:coewsc>2.0.co;2
fatcat:movy5rawhncqxdsdzhyzhnd2ae
Mean radiant temperature from global-scale numerical weather prediction models
2020
International journal of biometeorology
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Modelling cloud fraction and cloud types, for instance, is difficult and makes predicting radiation still a demanding task although significant improvements have been achieved (Hogan et al. 2009; Hogan ...
As described in the "Introduction", radiation quantities are stored as accumulated fluxes, i.e. as the energy that has passed through a square metre of a flat horizontal plane (units of J m −2 or W m − ...
doi:10.1007/s00484-020-01900-5
pmid:32274575
fatcat:wwqmvsermba3tc3opcyx7nqgka
Improved rain rate and drop size retrievals from airborne Doppler radar
2017
Atmospheric Chemistry and Physics
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Edited by: Timothy J. Dunkerton Reviewed by: Alain Protat and two anonymous referees ...
Multiple scattering effects on radar and lidar backscatter can be estimated within CAPTIVATE using Hogan (2008) . ...
Additionally, profiles of retrieved variables can be represented smoothly as a set of cubic spline basis functions (Hogan, 2007, and Sect. 2.3 .3). ...
doi:10.5194/acp-17-11567-2017
fatcat:q3be4p6uibhevplngvzy6tn7tm
A method to diagnose boundary-layer type using Doppler lidar
2013
Quarterly Journal of the Royal Meteorological Society
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J. R. Meteorol. Soc. 139: 1681-1693 (2013) ...
This is similar to the signature of decoupled stratocumulus cloud observed by Hogan et al. (2009) . ...
doi:10.1002/qj.2068
fatcat:mma7xob73vg6fbpnoka6mviyje
Parameterizing Ice Cloud Inhomogeneity and the Overlap of Inhomogeneities Using Cloud Radar Data
2003
Journal of the Atmospheric Sciences
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al. 2001) , and cloud overlap (Hogan and Illingworth 2000) . ...
Attenuation by the ice clouds themselves is negligible (Hogan and Illingworth 1999) . ...
doi:10.1175/1520-0469(2003)060<0756:piciat>2.0.co;2
fatcat:zs6c4jrz5fhnhjoilvbe6mqpcu
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