Download or read book Cloud Scale Numerical Modeling of the Arctic Boundary Layer written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-19 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research objective of this NASA grant-funded project was to determine in detail how large-scale processes. in combination with cloud-scale radiative, microphysical, and dynamical processes, govern the formation and multi-layered structure of Arctic stratus clouds. This information will be useful for developing and improving 1D (one dimensional) boundary layer models for the Arctic. Also, to quantitatively determine the effects of leads on the large-scale budgets of sensible heat, water vapor, and condensate in a variety of Arctic winter conditions. This information will be used to identify the most important lead-flux processes that require parameterization in climate models. Our approach was to use a high-resolution numerical model, the 2D (two dimensional) University of Utah Cloud Resolving Model (UU CRM), and its 1D version, the University of Utah Turbulence Closure Model (UU TCM), a boundary layer model based on third-moment turbulence closure, as well as a large-eddy simulation (LES) model originally developed by C.H. Moeng. Kruegen, Steven K. and Delnore, Victor E. (Technical Monitor) Langley Research Center

Download or read book Modeling of the Arctic Boundary Layer written by and published by . This book was released on 1997 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the recent 3 month Arctic Ocean Expedition (AOE-96) to the North Pole during the summer of 1996 an enormous amount of data collected on the Arctic planetary boundary layer. In preparation for the expedition, the authors have developed an expanded and quite flexible 1-D computer code based on the successful work of ReVelle and of ReVelle and Coulter on modeling of boundary layer ''bursting''. This new code, BLMARC (Boundary Layer, Mixing, Aerosols, Radiation and Clouds), explicitly includes the physical and chemical effects due to the presence of clouds, aerosols and associated air chemistry. Using data from AOE-96 and the model BLMARC, the authors have begun a systematic effort to compare observations of the high Arctic boundary layer against numerical modeling results. The preliminary results for case963 and case964 are quite promising. The second period exhibits what appears to be bursting effects in the temperature, the winds and in the aerosol concentration and the modeling efforts have shown a similar set of features as well. Current work also includes model experiments with BLMARC on the aerosol nucleation and growth in the Arctic PBL and cloud and fog formation.

Download or read book Cloudy Boundary Layers of the Arctic written by James O. Pinto and published by . This book was released on 1997 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Atmospheric Boundary Layer written by J. R. Garratt and published by Cambridge University Press. This book was released on 1994-04-21 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book gives a comprehensive and lucid account of the science of the atmospheric boundary layer (ABL). There is an emphasis on the application of the ABL to numerical modelling of the climate. The book comprises nine chapters, several appendices (data tables, information sources, physical constants) and an extensive reference list. Chapter 1 serves as an introduction, with chapters 2 and 3 dealing with the development of mean and turbulence equations, and the many scaling laws and theories that are the cornerstone of any serious ABL treatment. Modelling of the ABL is crucially dependent for its realism on the surface boundary conditions, and chapters 4 and 5 deal with aerodynamic and energy considerations, with attention to both dry and wet land surfaces and sea. The structure of the clear-sky, thermally stratified ABL is treated in chapter 6, including the convective and stable cases over homogeneous land, the marine ABL and the internal boundary layer at the coastline. Chapter 7 then extends the discussion to the cloudy ABL. This is seen as particularly relevant, since the extensive stratocumulus regions over the subtropical oceans and stratus regions over the Arctic are now identified as key players in the climate system. Finally, chapters 8 and 9 bring much of the book's material together in a discussion of appropriate ABL and surface parameterization schemes in general circulation models of the atmosphere that are being used for climate simulation.

Download or read book Modelling and Observations of the Atmospheric Boundary Layer of the Arctic Marginal Ice Zone written by Rhiannon Davies and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of Arctic Stratus Cloud Formation and the Maintenance of the Cloudy Arctic Boundary Layer written by Chʻiu-chʻing Chang and published by . This book was released on 1999 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The formation of Arctic stratus clouds (ASC) and the maintenance of the cloudy Arctic boundary layer are studied with two models: a one-dimensional radiative-convective model and a three-dimensional large eddy simulation (LES) model. The one-dimensional radiative-convective model consists of a comprehensive radiative module, a cloud parameterization with detailed microphysics and a convective adjustment scheme. The model is designed specifically for studying ASC formation. With this model, the roles of radiation and cloud microphysics in the formation of ASCs and multiple cloud layers are investigated. The simulations reproduce both single and multiple cloud layers that were observed with inversions of temperature and humidity occurring near the cloud top. The detailed cloud microstructure produced by the model also compares well with the observations. The physics of the formation of both single and multiple cloud layers is investigated. Radiative cooling plays a key role during the initial stage of cloud formation in a atmosphere. It leads to a continual temperature decrease promoting water vapor condensation on available cloud condensation nuclei. The vertical distribution of humidity and temperature determines the radiative cooling and eventually where and when the cloud forms. The observed temperature inversion may also be explained by radiative cooling. The three-dimensional LES model is adopted to evaluate the one-dimensional model, especially the convective adjustment scheme. The advantages and limitations of the one-dimensional model are discussed. The LES results suggest that the convective adjustment scheme is capable of capturing the main features of the vertical heat and moisture fluxes in the cloudy Arctic boundary layer. The LES model is also used to investigate the maintenance of the cloudy Arctic boundary layer. The turbulence in the cloudy Arctic boundary layer is primarily maintained by the bouyancy effect due to the cloud top cooling. It is found that weak large scale downward motion aids in cloud development and maintenance"--3.

Download or read book Large Eddy Simulations of the Arctic Boundary Layer Around the MOSAiC Drift Track written by Daniela-Christin Littmann and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The icosahedral non-hydrostatic large eddy model (ICON-LEM) was applied around the drift track of the Multidisciplinary Observatory Study of the Arctic (MOSAiC) in 2019 and 2020. The model was set up with horizontal grid-scales between 100m and 800m on areas with radii of 17.5km and 140 km. At its lateral boundaries, the model was driven by analysis data from the German Weather Service (DWD), downscaled by ICON in limited area mode (ICON-LAM) with horizontal grid-scale of 3 km. The aim of this thesis was the investigation of the atmospheric boundary layer near the surface in the central Arctic during polar winter with a high-resolution mesoscale model. The default settings in ICON-LEM prevent the model from representing the exchange processes in the Arctic boundary layer in accordance to the MOSAiC observations. The implemented sea-ice scheme in ICON does not include a snow layer on sea-ice, which causes a too slow response of the sea-ice surface temperature to atmospheric changes. [...].

Download or read book Study of the Planetary Boundary Layer Using GEM Model Simulations in Support of Wind Power Projections for the Canadian Arctic written by Caio Ruman and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Temperature inversions are a common feature of the Arctic climate, affecting the surface energy budget and planetary boundary layer transports. The temperature inversion, in conjunction with the wind, is used to define the transition between two stable planetary boundary layer regimes, the weakly stable boundary layer, and the very stable boundary layer. This regime shift is sharply defined in terms of wind speed and temperature inversions, so accurate modeling of those two characteristics is crucial to a good representation of the Arctic climate. This study investigates the evolution of large-scale temperature inversions in the context of a changing climate, in support of wind power projections for the Canadian Arctic. To this end, two five-member Regional Climate Model (RCM) ensembles, driven by the Canadian Earth System Model, spanning the 1950-2099 period, corresponding to two greenhouse gas emission scenarios (RCP 4.5 and 8.5), are considered. An ERA-Interim driven simulation for the 1979-2005 period is also considered to assess model performance. A comparison of observed atmospheric soundings with the boundary layer variations in the reanalysis-driven simulation indicates that the model captures the temperature inversion characteristics reasonably well, with some positive biases in the temperature inversion strength and frequency. The transient regional climate change simulations suggest substantial decreases in both temperature inversion strength and frequency in winter in future climate for both emission scenarios. These changes are consistent with the reduced sea ice cover and the associated increase in cloud cover that reduce the surface radiative cooling necessary for the formation of strong temperature inversions. Some increases in the frequency and strength of temperature inversions are projected for summer over the Arctic Ocean, possibly linked with increased poleward moisture transport. With the changes in the Arctic atmosphere seen in the future climate, the current predominant clear cold atmospheric state becomes less frequent. Cloudy and warm conditions that inhibit the formation of temperature inversions become more common. This scenario will increase the frequency of the atmospheric regime where temperature inversions are weaker and the wind speed is higher, leading to increased wind power potential to the Arctic region and positive prospects to a transition to a clean energy regimen"--

Download or read book An Observation and Modeling Study of Arctic Multilayered Mixed phase Boundary Layer Clouds written by Hui Lai and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To better understand the dynamic and thermodynamic processes that form and maintain Arctic multilayered mixed-phase clouds, Moderate Resolution Imaging Spectroradiometer (MODIS) radiances, High Spectral Resolution Lidar (HSRL) backscatter, and Ka-band ARM zenith radar (KAZR) returns along with balloon-borne sounding thermodynamic profiles, were analyzed from 1-3 May 2013. The observations, together with ERA-Interim Reanalysis data, indicate that three cloud regimes were present during this period. Frontal clouds occurred in a north to south band with Barrow located on their eastern edge at 00:00 UTC 2 May. By mid-day the frontal clouds had moved into the Barrow region. A broad low-altitude stratus deck existed to the west and north of Barrow, advecting into the Barrow region by the end of 2 May as the frontal clouds cleared the region. The stratus deck remained over Barrow throughout 3 May and several days beyond it. Boundary layer cellular convection was the predominant cloud type in the vicinity of the low pressure to the east and north of Barrow on 1-2 May.On 2 May 2013 shallow single- and multi-layered, mixed-phase clouds observed by the HSRL and KAZR were present above Barrow, Alaska, leading at various times to pristine crystals, rimed crystals and aggregates of crystals at the surface. During this case study period, a weak surface trough was located to the north and east of Barrow with a high pressure ridge to its west. The associated surface front was located over Barrow and extended to the north over the Arctic Ocean. High spatial (250-m) pixel resolution MODIS radiances show low level cloud streets in the vicinity of Barrow and just to its east oriented perpendicular to the mean wind around 00:00 UTC 2 May. Low altitude cloud streets also existed to the west of Barrow at this time, though oriented parallel to the mean wind. Finally, additional cloud streets to the southwest of Barrow and perpendicular to the mean wind also were present but in the higher altitude frontal clouds. The low altitude cloud streets just to the east and west of Barrow, and under the frontal cloud layer, were the source of the multilayered clouds on this day; this study focused on the ones to the west. These cloud streets formed in an environment of strong vertical wind shear with an underlying shallow buoyant layer near the surface.The Weather and Research Forecasting (WRF) model was used to conduct mesoscale simulations for this day and the two surrounding ones. For the three-day period from 1-3 May 2013 the 27-km spatial grid spacing WRF model reproduced mesoscale geopotential height, wind, relative humidity and sea-level pressure fields similar to those contained in the (0.75 lat/lon) ERA-Interim Reanalysis. Moreover, the model was able to reproduce the three cloud systems evident in the observations: the low cloud-liquid stratus to the west of Barrow, the deep frontal cloud layer in the vicinity of Barrow, and the more convective cloud cells with heights in-between to the east of Barrow.In the WRF modeling approach six nested domains were used with horizontal grid spacings starting from 27 km and scaling down in ratios of 3 to 1, with the finest domain run in large eddy simulation mode at 111-m horizontal grid spacing in an attempt to capture the short (~ 1.5-km) wavelength of the cloud streets apparent in the satellite data. Model results show that warm air advection and surface radiative heating created enhanced near surface instability, providing the buoyancy necessary to drive the initial convection. These buoyant parcels entered the region of strong vertical shear, leading to Richardson numbers around 0.2 and the conditions favorable for the formation of roll clouds. The wavelengths of the roll clouds produced by the inner four nested domains varied from 33 km for the outermost 3-km domain to 1 km for the finest 0.111-km grid spacing domain. The finest grid spacing domain roll-cloud wavelengths were comparable to those observed by MODIS, illustrating the necessity of using a grid spacing sufficiently small to place at least 7 to 10 grid points across a roll in order to resolve it.

Download or read book Sea Ice written by David N. Thomas and published by John Wiley & Sons. This book was released on 2017-03-06 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past 20 years the study of the frozen Arctic and Southern Oceans and sub-arctic seas has progressed at a remarkable pace. This third edition of Sea Ice gives insight into the very latest understanding of the how sea ice is formed, how we measure (and model) its extent, the biology that lives within and associated with sea ice and the effect of climate change on its distribution. How sea ice influences the oceanography of underlying waters and the influences that sea ice has on humans living in Arctic regions are also discussed. Featuring twelve new chapters, this edition follows two previous editions (2001 and 2010), and the need for this latest update exhibits just how rapidly the science of sea ice is developing. The 27 chapters are written by a team of more than 50 of the worlds’ leading experts in their fields. These combine to make the book the most comprehensive introduction to the physics, chemistry, biology and geology of sea ice that there is. This third edition of Sea Ice will be a key resource for all policy makers, researchers and students who work with the frozen oceans and seas.

Download or read book Numerical Modeling and Observations of Atmospheric Boundary Layer Over Sea Ice written by Marta Aleksandra Wenta and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interactions of the Cloudy Arctic Boundary Layer with Variable Surface Conditions and Large Scale Circulations written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-16 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our project included a variety of activities, ranging from model development to data manipulation and even participation in the SHEBA and FIRE field experiments. The following sections outline the work accomplished under these tasks. A collection of reprints is attached to this report. Randell, David A. Langley Research Center

Download or read book Atmospheric Boundary Layers written by Alexander Baklanov and published by Springer Science & Business Media. This book was released on 2007-10-30 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents peer-reviewed papers from the NATO Advanced Research Workshop on Atmospheric Boundary Layers held in April 2006. The papers are divided into thematic sessions: nature and theory of turbulent boundary layers; boundary-layer flows: modeling and applications to environmental security; nature, theory and modeling of boundary-layer flows; air flows within and above urban and other complex canopies: air-sea-ice interaction.

Download or read book Oceanic and Atmospheric Boundary Layer Study written by M. D. Coon and published by . This book was released on 1974 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The AIDJEX Modeling Group is developing a predictive model of the dynamics and thermodynamics of the arctic ice cover. To date, an elastic-plastic model of the ice behavior has been developed and operated using field data from AIDJEX pilot programs. A complete model using air stress, water stress, and momentum balance for the ice pack will be developed by the spring of 1975 and checked against the AIDJEX field data taken in a year-long experiment from spring 1975 to spring 1976. (Author).

Download or read book Ice at the Interface written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The atmosphere-ocean boundary layer in which sea ice resides includes many complex processes that require a more realistic treatment in GCMs, particularly as models move toward full earth system descriptions. The primary purpose of the workshop was to define and discuss such coupled processes from observational and modeling points of view, including insight from both the Arctic and Antarctic systems. The workshop met each of its overarching goals, including fostering collaboration among experimentalists, theorists and modelers, proposing modeling strategies, and ascertaining data availability and needs. Several scientific themes emerged from the workshop, such as the importance of episodic or extreme events, precipitation, stratification above and below the ice, and the marginal ice zone, whose seasonal Arctic migrations now traverse more territory than in the past.

Download or read book A Time dependent Air water Boundary Layer Model written by Canada. Atmospheric Environment Service and published by montreal : arctic meteorology research group, mcgill university. This book was released on 1973 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Arctic Climate Change written by Peter Lemke and published by Springer Science & Business Media. This book was released on 2011-11-22 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Arctic is now experiencing some of the most rapid and severe climate change on earth. Over the next 100 years, climate change is expected to accelerate, contributing to major physical, ecological, social, and economic changes, many of which have already begun. Changes in arctic climate will also affect the rest of the world through increased global warming and rising sea levels. The volume addresses the following major topics: - Research results in observing aspects of the Arctic climate system and its processes across a range of time and space scales - Representation of cryospheric, atmospheric, and oceanic processes in models, including simulation of their interaction with coupled models - Our understanding of the role of the Arctic in the global climate system, its response to large-scale climate variations, and the processes involved.