From surface data to bulk properties: a case study for antiphase boundaries in GaP on Si(001)

2021 ◽  
Vol 54 (20) ◽  
pp. 205302 ◽  
Author(s):  
P Farin ◽  
H Eisele ◽  
M Dähne ◽  
A Lenz
Keyword(s):  
Antiphase Boundaries ◽  
Bulk Properties ◽  
Surface Data

scholarly journals The Impact of Data Assimilation on WRF Simulation using Surface Data and Radar Data: Case Study

Atmosphere ◽  
2013 ◽  
Vol 23 (2) ◽  
pp. 143-160 ◽  
Author(s):  
Won Choi ◽  
Jae Gyoo Lee ◽  
Yu-Jin Kim
Keyword(s):  
Data Assimilation ◽  
Radar Data ◽  
Surface Data ◽  
The Impact

scholarly journals A Case Study of Subtropical Frontogenesis during a Blocking Event

2007 ◽  
Vol 135 (7) ◽  
pp. 2588-2609 ◽  
Author(s):  
George Tai-Jen Chen ◽  
Chung-Chieh Wang ◽  
An-Hsiang Wang
Keyword(s):  
Large Scale ◽  
Frontal Zone ◽  
Southern China ◽  
Sensible Heat Flux ◽  
Northern China ◽  
Sensible Heat ◽  
Surface Data ◽  
Sea Area ◽  
Blocking Event

Abstract During 8–14 June 2000, a 500-hPa blocking event occurred over Mongolia and northern China (near 45°N, 108°E), which was the only case over this region in June since 1981. As the block developed, the initially weak low-level mei-yu front over southern China evolved into a system with strong baroclinity and subsequently moved south. The frontal passage over Taiwan caused temperatures to drop by 10°C, the largest in June over two decades. Using gridded analyses, manually analyzed weather maps, and satellite and surface data, the present study investigates the evolution of this mei-yu front under the influence of the block. The 925-hPa frontogenetical function is computed and effects of different processes are discussed. As the blocking event developed, concurrent ridge–trough amplification in the lower–midtroposphere produced a reversed thermal pattern. The lower-tropospheric high moved southward, and large-scale confluence and deformation were enhanced between the northerly flow and the prefrontal southwesterly flow. The location of the block, to the west-southwest of the Okhotsk Sea area, allowed it to affect the front over southern China and caused it to penetrate inside 20°N, unusual for the month of June. The distribution of the frontogenetical function indicated that the mei-yu frontogenesis and the maintenance of the front were attributed to both deformation and convergence. These two processes together counteracted the strong frontolysis along the frontal zone from diabatic effects, caused by evaporative cooling of frontal precipitation on the warm side and stronger sensible heat transfer (and daytime heating over less cloudy areas) on the cold side of the front. When deformation, convergence, and diabatic effects were all combined, the net total frontogenesis peaked slightly ahead of the frontal zone, thus contributing to the southward propagation of the front in addition to the advection by postfrontal cold air in the present case. When the front moved into the South China Sea, the cross-frontal thermal gradient diminished rapidly, mainly due to the frontolytic effect from sensible heat flux over warm waters.

scholarly journals A 20-Year Climatology of Nocturnal Convection Initiation over the Central and Southern Great Plains during the Warm Season

2017 ◽  
Vol 145 (5) ◽  
pp. 1615-1639 ◽  
Author(s):  
Dylan W. Reif ◽  
Howard B. Bluestein
Keyword(s):  
Great Plains ◽  
Warm Season ◽  
Thunderstorm Activity ◽  
Surface Boundary ◽  
Initiation Time ◽  
Southern Great Plains ◽  
Surface Data ◽  
Convection Initiation ◽  
Storm Characteristics

Abstract A nocturnal maximum in rainfall and thunderstorm activity over the central Great Plains has been widely documented, but the mechanisms for the development of thunderstorms over that region at night are still not well understood. Elevated convection above a surface frontal boundary is one explanation, but this study shows that many thunderstorms form at night without the presence of an elevated frontal inversion or nearby surface boundary. This study documents convection initiation (CI) events at night over the central Great Plains from 1996 to 2015 during the months of April–July. Storm characteristics such as storm type, linear system orientation, initiation time and location, and others were documented. Once all of the cases were documented, surface data were examined to locate any nearby surface boundaries. The event’s initiation location relative to these boundaries (if a boundary existed) was documented. Two main initiation locations relative to a surface boundary were identified: on a surface boundary and on the cold side of a surface boundary; CI events also occur without any nearby surface boundary. There are many differences among the different nocturnal CI modes. For example, there appear to be two main peaks of initiation time at night: one early at night and one later at night. The later peak is likely due to the events that form without a nearby surface boundary. Finally, a case study of three nocturnal CI events that occurred during the Plains Elevated Convection At Night (PECAN) field project when there was no nearby surface boundary is discussed.

scholarly journals Using surface velocities to calculate ice thickness and bed topography: a case study at Columbia Glacier, Alaska, USA

2012 ◽  
Vol 58 (212) ◽  
pp. 1151-1164 ◽  
Author(s):  
R.W. Mcnabb ◽  
R. Hock ◽  
S. O’Neel ◽  
L.A. Rasmussen ◽  
Y. Ahn ◽  
...  
Keyword(s):  
Thickness Distribution ◽  
Computational Time ◽  
Ice Thickness ◽  
Thickness Change ◽  
Bed Topography ◽  
Surface Data ◽  
Direct Measurements ◽  
The Mean ◽  
Time Required

AbstractInformation about glacier volume and ice thickness distribution is essential for many glaciological applications, but direct measurements of ice thickness can be difficult and costly. We present a new method that calculates ice thickness via an estimate of ice flux. We solve the familiar continuity equation between adjacent flowlines, which decreases the computational time required compared to a solution on the whole grid. We test the method on Columbia Glacier, a large tidewater glacier in Alaska, USA, and compare calculated and measured ice thicknesses, with favorable results. This shows the potential of this method for estimating ice thickness distribution of glaciers for which only surface data are available. We find that both the mean thickness and volume of Columbia Glacier were approximately halved over the period 1957–2007, from 281 m to 143 m, and from 294 km3 to 134 km3, respectively. Using bedrock slope and considering how waves of thickness change propagate through the glacier, we conduct a brief analysis of the instability of Columbia Glacier, which leads us to conclude that the rapid portion of the retreat may be nearing an end.

Data Fusion of GEO FY4A GIIRS and LEO Hyperspectral Infrared Sounders with Surface Observations: A Hong Kong Case Study

2021 ◽  
Keyword(s):  
Hong Kong ◽  
Water Vapor ◽  
Weather Prediction ◽  
Coastal Region ◽  
Sampling Interval ◽  
Surface Data ◽  
Accurate Temperature ◽  
Rapid Transition ◽  
Surface Observations

Abstract Hyperspectral infrared satellite observations from geostationary platforms allow for the retrieval of temperature and water vapor measurements with higher temporal and vertical resolution than was previously available. The Chinese satellite, FY-4A includes the Geostationary Interferometric Infrared Sounder (GIIRS) which has the ability to measure vertical profiles of temperature and water vapor from space at times when ground-based upper air soundings are not available and can fill an important need in short-range weather prediction. In this study, CAPE and LI, which are used for forecasting atmospheric instability, were computed using the SHARPpy algorithm used by the NWS Storm Prediction Center. However, remote infrared and microwave sensing is lacking detailed information in the boundary layer, so the addition of the NOAA MADIS surface data may be necessary in order to get accurate temperature and moisture measurement near the surface. This study uses May 10-16, 2019 in the coastal region near Hong Kong for evaluating the use of hourly surface observations combined with satellite soundings from FY4A GIIRS at two hour intervals. The GIIRS plus MADIS surface-based CAPE and LI estimates are compared to estimates derived from low earth orbiting (LEO) SNPP and NOAA20 from NOAA, METOP from EUMETSAT, NWP reanalysis, and local radiosondes. In the case study, the two-hour sampling interval of the GIIRS geostationary sounder was able to capture the rapid transition (16 hours) from stable to unstable atmosphere in both CAPE and LI. The use of surface observations with satellite soundings gave mixed results, possibly due to the complex terrain near Hong Kong.

scholarly journals Source Apportionment of Aerosol at a Coastal Site and Relationships with Precipitation Chemistry: A Case Study over the Southeast United States

Atmosphere ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1212
Author(s):  
Andrea F. Corral ◽  
Hossein Dadashazar ◽  
Connor Stahl ◽  
Eva-Lou Edwards ◽  
Paquita Zuidema ◽  
...  
Keyword(s):  
Precipitation Chemistry ◽  
Sea Salt ◽  
Strongly Correlated ◽  
Southeast United States ◽  
Deposition Fluxes ◽  
Pmf Model ◽  
Surface Data ◽  
Southern Florida

This study focuses on the long-term aerosol and precipitation chemistry measurements from colocated monitoring sites in Southern Florida between 2013 and 2018. A positive matrix factorization (PMF) model identified six potential emission sources impacting the study area. The PMF model solution yielded the following source concentration profiles: (i) combustion; (ii) fresh sea salt; (iii) aged sea salt; (iv) secondary sulfate; (v) shipping emissions; and (vi) dust. Based on these results, concentration-weighted trajectory maps were developed to identify sources contributing to the PMF factors. Monthly mean precipitation pH values ranged from 4.98 to 5.58, being positively related to crustal species and negatively related to SO42−. Sea salt dominated wet deposition volume-weighted concentrations year-round without much variability in its mass fraction in contrast to stronger seasonal changes in PM2.5 composition where fresh sea salt was far less influential. The highest mean annual deposition fluxes were attributed to Cl−, NO3−, SO42−, and Na+ between April and October. Nitrate is strongly correlated with dust constituents (unlike sea salt) in precipitation samples, indicative of efficient partitioning to dust. Interrelationships between precipitation chemistry and aerosol species based on long-term surface data provide insight into aerosol–cloud–precipitation interactions.

RESERVOIR MANAGEMENT OF SUBSEA DEVELOPMENT FIELDS IN THE TIMOR SEA

1993 ◽  
Vol 33 (1) ◽  
pp. 363
Author(s):  
G.J. Chapman
Keyword(s):  
Reservoir Management ◽  
Continuous Development ◽  
Reservoir Performance ◽  
Surface Data ◽  
Survey Costs ◽  
Timor Sea

In a subsea development, downhole survey costs are high but the reservoir management requirements are basically the same as those for fields developed onshore or by a platform. This paper describes techniques employed to monitor reservoir performance of a field with a subsea style development, primarily by the utilisation of surface data, supplemented by selected downhole data. Along with a number of field examples, from the Timor Sea, a case study of the recently commissioned Skua Field is presented which demonstrates these techniques and how they were applied to enable effective reservoir management of this subsea development. These techniques include the determination of reservoir pressures, reservoir communication and changing well productivities using surface pressures to evaluate the extent of aquifer support. This data is supported by analytical and numerical reservoir studies to provide an understanding of reservoir performance and to facilitate the continuous development requirements of a producing field and to optimise the recovery of reserves.

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