scholarly journals An assessment of ECMWF analyses and model forecasts over the North Slope of Alaska using observations from the ARM Mixed-Phase Arctic Cloud Experiment

2006 ◽  
Vol 111 (D5) ◽  
Author(s):  
Shaocheng Xie ◽  
Stephen A. Klein ◽  
John J. Yio ◽  
Anton C. M. Beljaars ◽  
Charles N. Long ◽  
...  
Keyword(s):  
Mixed Phase ◽  
North Slope ◽  
The North ◽  
North Slope Of Alaska

scholarly journals Statistical Analysis of Forecasting Models across the North Slope of Alaska during the Mixed-Phase Arctic Clouds Experiment

2009 ◽  
Vol 24 (6) ◽  
pp. 1644-1663 ◽  
Author(s):  
Victor T. Yannuzzi ◽  
Eugene E. Clothiaux ◽  
Jerry Y. Harrington ◽  
Johannes Verlinde
Keyword(s):  
Cloud Cover ◽  
Atmospheric Modeling ◽  
Mixed Phase ◽  
North Slope ◽  
Model Errors ◽  
Unique Challenge ◽  
Arctic Clouds ◽  
Forecasting Models ◽  
The North ◽  
North Slope Of Alaska

Abstract The National Centers for Environmental Prediction’s (NCEP) Eta Model, the models of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Aeronautics and Space Administration’s (NASA) Global Modeling and Assimilation Office (GMAO) models, and the Regional Atmospheric Modeling System (RAMS) model are all examined during the Mixed-Phase Arctic Clouds Experiment (MPACE) that took place from 27 September through 22 October 2004. During two intensive observation periods, soundings were launched every 6 h from four sites across the North Slope of Alaska (NSA): Barrow, Atqasuk, Oliktok Point, and Toolik Lake. Measurements of temperature, moisture, and winds, along with surface measurements of radiation and cloud cover, were compared to model outputs from the Eta, ECMWF, GMAO, and RAMS models using the bootstrap statistical technique to ascertain if differences in model performance were statistically significant. Ultimately, three synoptic regimes controlled NSA weather during the MPACE period for varying amounts of time. Each posed a unique challenge to the forecasting models during the study period. Temperature forecasts for all models were good at the MPACE sites with mean bias errors generally under 2 K, and the models had the fewest significant errors predicting temperature. Forecasting moisture and wind proved to be more difficult for the models, especially aloft in the 500–300-hPa layer. The largest errors occurred in the GMAO model, with significant moist biases of 40% and wind errors of 10 m s−1 or more. The RAMS, Eta, and ECMWF models had smaller moist biases in this layer. Both the Eta and RAMS models overestimated the surface incident shortwave radiation, underestimated longwave radiation, and underestimated cloud cover fraction. Overall, the bootstrapping results coincided with findings from conventional statistical comparisons as model outputs with the largest errors were most likely to be captured and declared statistically significant in the bootstrapping process. The significant model errors during MPACE were predominantly traced to the inability of the models to simulate disturbances in synoptic regime I, warm or cold biases over higher inland terrain, a warm bias along the NSA coastal waters in the Beaufort Sea, and difficulty in forecasting the intensity of the explosive cyclone in synoptic regime III.

Dispersive noise removal in t-x space: Application to Arctic data

Geophysics ◽  
1988 ◽  
Vol 53 (3) ◽  
pp. 346-358 ◽  
Author(s):  
Greg Beresford‐Smith ◽  
Rolf N. Rango
Keyword(s):  
Signal To Noise Ratio ◽  
Noise Analysis ◽  
Noise Removal ◽  
North Slope ◽  
Frequency Bandwidth ◽  
The North ◽  
North Slope Of Alaska ◽  
Seismic Records ◽  
Time Offset ◽  
Undersampled Data

Strongly dispersive noise from surface waves can be attenuated on seismic records by Flexfil, a new prestack process which uses wavelet spreading rather than velocity as the criterion for noise discrimination. The process comprises three steps: trace‐by‐trace compression to collapse the noise to a narrow fan in time‐offset (t-x) space; muting of the noise in this narrow fan; and inverse compression to recompress the reflection signals. The process will work on spatially undersampled data. The compression is accomplished by a frequency‐domain, linear operator which is independent of trace offset. This operator is the basis of a robust method of dispersion estimation. A flexural ice wave occurs on data recorded on floating ice in the near offshore of the North Slope of Alaska. It is both highly dispersed and of broad frequency bandwidth. Application of Flexfil to these data can increase the signal‐to‐noise ratio up to 20 dB. A noise analysis obtained from a microspread record is ideal to use for dispersion estimation. Production seismic records can also be used for dispersion estimation, with less accurate results. The method applied to field data examples from Alaska demonstrates significant improvement in data quality, especially in the shallow section.

InSAR measurements of surface deformation over permafrost on the North Slope of Alaska

2010 ◽  
Vol 115 (F3) ◽  
Author(s):  
Lin Liu ◽  
Tingjun Zhang ◽  
John Wahr
Keyword(s):  
Surface Deformation ◽  
North Slope ◽  
The North ◽  
North Slope Of Alaska

Cloud Properties over the North Slope of Alaska: Identifying the Prevailing Meteorological Regimes

2012 ◽  
Vol 25 (23) ◽  
pp. 8238-8258 ◽  
Author(s):  
Johannes Mülmenstädt ◽  
Dan Lubin ◽  
Lynn M. Russell ◽  
Andrew M. Vogelmann
Keyword(s):  
Time Series ◽  
Climate Model ◽  
North Slope ◽  
Test Cases ◽  
Synoptic Scale ◽  
Long Time Series ◽  
The North ◽  
Cloud Properties ◽  
North Slope Of Alaska ◽  
Long Time

Abstract Long time series of Arctic atmospheric measurements are assembled into meteorological categories that can serve as test cases for climate model evaluation. The meteorological categories are established by applying an objective k-means clustering algorithm to 11 years of standard surface-meteorological observations collected from 1 January 2000 to 31 December 2010 at the North Slope of Alaska (NSA) site of the U.S. Department of Energy Atmospheric Radiation Measurement Program (ARM). Four meteorological categories emerge. These meteorological categories constitute the first classification by meteorological regime of a long time series of Arctic meteorological conditions. The synoptic-scale patterns associated with each category, which include well-known synoptic features such as the Aleutian low and Beaufort Sea high, are used to explain the conditions at the NSA site. Cloud properties, which are not used as inputs to the k-means clustering, are found to differ significantly between the regimes and are also well explained by the synoptic-scale influences in each regime. Since the data available at the ARM NSA site include a wealth of cloud observations, this classification is well suited for model–observation comparison studies. Each category comprises an ensemble of test cases covering a representative range in variables describing atmospheric structure, moisture content, and cloud properties. This classification is offered as a complement to standard case-study evaluation of climate model parameterizations, in which models are compared against limited realizations of the Earth–atmosphere system (e.g., from detailed aircraft measurements).

Underbalanced Drilling with Coiled Tubing: A Case Study on the Alaskan North Slope, Which Proves the Benefits of Drilling a Straight Hole

2021 ◽  
Author(s):  
Antoni Miszewski ◽  
Adam Miszewski ◽  
Richard Stevens ◽  
Matteo Gemignani
Keyword(s):  
Relative Effectiveness ◽  
Shallow Depth ◽  
North Slope ◽  
Coiled Tubing ◽  
The North ◽  
North Slope Of Alaska ◽  
Minimum Requirements ◽  
Bottom Hole Assembly ◽  
Alaskan North Slope ◽  
Future Work

Abstract A set of 5 wells were to be drilled with directional Coiled Tubing Drilling (CTD) on the North Slope of Alaska. The particular challenges of these wells were the fact that the desired laterals were targeted to be at least 6000ft long, at a shallow depth. Almost twice the length of laterals that are regularly drilled at deeper depths. The shallow depth meant that 2 of the 5 wells involved a casing exit through 3 casings which had never been attempted before. After drilling, the wells were completed with a slotted liner, run on coiled tubing. This required a very smooth and straight wellbore so that the liner could be run as far as the lateral had been drilled. Various methods were considered to increase lateral reach, including, running an extended reach tool, using friction reducer, increasing the coiled tubing size and using a drilling Bottom Hole Assembly (BHA) that could drill a very straight well path. All of these options were modelled with tubing forces software, and their relative effectiveness was evaluated. The drilling field results easily exceeded the minimum requirements for success. This project demonstrated record breaking lateral lengths, a record length of liner run on coiled tubing in a single run, and a triple casing exit. The data gained from this project can be used to fine-tune the modelling for future work of a similar nature.

Changes in tall shrub abundance on the North Slope of Alaska, 2000–2010

2018 ◽  
Vol 219 ◽  
pp. 221-232 ◽  
Author(s):  
Rocio R. Duchesne ◽  
Mark J. Chopping ◽  
Ken D. Tape ◽  
Zhuosen Wang ◽  
Crystal L.B. Schaaf
Keyword(s):  
North Slope ◽  
The North ◽  
North Slope Of Alaska ◽  
Tall Shrub

Effects of Climate on the Active Layer and Permafrost on the North Slope of Alaska, U.S.A.

1997 ◽  
Vol 8 (1) ◽  
pp. 45-67 ◽  
Author(s):  
T. Zhang ◽  
T. E. Osterkamp ◽  
K. Stamnes
Keyword(s):  
Active Layer ◽  
North Slope ◽  
The North ◽  
North Slope Of Alaska

scholarly journals Two oil types on the North Slope of Alaska: implications for future exploration

1979 ◽  
Author(s):  
Leslie B. Magoon ◽  
George Edwin Claypool
Keyword(s):  
North Slope ◽  
The North ◽  
North Slope Of Alaska

scholarly journals Processes contributing to cloud dissipation and formation events on the North Slope of Alaska

2021 ◽  
Vol 21 (5) ◽  
pp. 4149-4167
Author(s):  
Joseph Sedlar ◽  
Adele Igel ◽  
Hagen Telg
Keyword(s):  
Cloud Formation ◽  
North Slope ◽  
Near Surface ◽  
Air Mass ◽  
Low Level ◽  
Clear Sky ◽  
The North ◽  
Synoptic Conditions ◽  
North Slope Of Alaska ◽  
Low Cloud

Abstract. Clear-sky periods across the high latitudes have profound impacts on the surface energy budget and lower atmospheric stratification; however an understanding of the atmospheric processes leading to low-level cloud dissipation and formation events is limited. A method to identify clear periods at Utqiaġvik (formerly Barrow), Alaska, during a 5-year period (2014–2018) is developed. A suite of remote sensing and in situ measurements from the high-latitude observatory are analyzed; we focus on comparing and contrasting atmospheric properties during low-level (below 2 km) cloud dissipation and formation events to understand the processes controlling clear-sky periods. Vertical profiles of lidar backscatter suggest that aerosol presence across the lower atmosphere is relatively invariant during the periods bookending clear conditions, which suggests that a sparsity of aerosol is not frequently a cause for cloud dissipation on the North Slope of Alaska. Further, meteorological analysis indicates two active processes ongoing that appear to support the formation of low clouds after a clear-sky period: namely, horizontal advection, which was dominant in winter and early spring, and quiescent air mass modification, which was dominant in the summer. During summer, the dominant mode of cloud formation is a low cloud or fog layer developing near the surface. This low cloud formation is driven largely by air mass modification under relatively quiescent synoptic conditions. Near-surface aerosol particles concentrations changed by a factor of 2 around summer formation events. Thermodynamic adjustment and increased aerosol presence under quiescent atmospheric conditions are hypothesized as important mechanisms for fog formation.

Brood Rearing Ecology of King Eiders on the North Slope of Alaska

2009 ◽  
Vol 121 (2) ◽  
pp. 430-434 ◽  
Author(s):  
Laura M. Phillips ◽  
Abby N. Powell
Keyword(s):  
North Slope ◽  
Brood Rearing ◽  
The North ◽  
North Slope Of Alaska
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