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nearby Arctic Ocean and typically overflew the surface Atmospheric Radiation Measurement (ARM) site in Barrow, Alaska, en route to and from the SHEBA ice station. The main objectives of the ER-2 included (i) comparing the spectral properties of sea ice, tundra, and cloud layers; (ii) collecting MAS data to verify the MODIS cloud mask algorithm for distinguishing clouds from snow and sea ice surfaces in polar regions; (iii) collecting data for retrieving cloud radiative and microphysical properties
nearby Arctic Ocean and typically overflew the surface Atmospheric Radiation Measurement (ARM) site in Barrow, Alaska, en route to and from the SHEBA ice station. The main objectives of the ER-2 included (i) comparing the spectral properties of sea ice, tundra, and cloud layers; (ii) collecting MAS data to verify the MODIS cloud mask algorithm for distinguishing clouds from snow and sea ice surfaces in polar regions; (iii) collecting data for retrieving cloud radiative and microphysical properties
1. Introduction It has been previously shown that the two-satellite system on a Molniya-type highly elliptical orbit (HEO) with a 12-h period can provide continuous observations of the Arctic region above approximately 58Β° and 38Β°N for the maximum viewing zenith angles of 70Β° and 90Β°, respectively ( Trishchenko and Garand 2011 ). In other words, one or two satellites are seen above the horizon (at 0Β° elevation) or at 20Β° elevation at any particular point in time within latitude circles of 38
1. Introduction It has been previously shown that the two-satellite system on a Molniya-type highly elliptical orbit (HEO) with a 12-h period can provide continuous observations of the Arctic region above approximately 58Β° and 38Β°N for the maximum viewing zenith angles of 70Β° and 90Β°, respectively ( Trishchenko and Garand 2011 ). In other words, one or two satellites are seen above the horizon (at 0Β° elevation) or at 20Β° elevation at any particular point in time within latitude circles of 38
Estimating Random Uncertainty in Airborne Flux Measurements over Alaskan Tundra: Update on the Flux Fragment Methodis considerably aided by airborne measurements. The value of airborne measurement of greenhouse-gas emissions from small aircraft at low altitude over the Arctic tundra has long been evident ( Zulueta et al. 2011 ; Oechel et al. 2000 , 1998 ; Brooks et al. 1997 ). The drivers are the difficulty in accessing large areas of tundra, the low relief of terrain, and the high amplitude of spatial heterogeneity in the fluxes. Improvements in the ability to measure methane as well as isotopologue
is considerably aided by airborne measurements. The value of airborne measurement of greenhouse-gas emissions from small aircraft at low altitude over the Arctic tundra has long been evident ( Zulueta et al. 2011 ; Oechel et al. 2000 , 1998 ; Brooks et al. 1997 ). The drivers are the difficulty in accessing large areas of tundra, the low relief of terrain, and the high amplitude of spatial heterogeneity in the fluxes. Improvements in the ability to measure methane as well as isotopologue
terrestrialβocean interfaces, and be used for targets of opportunity (e.g., flooding, fires, and land use changes). Flux measurement sites are typically selected within predominant or ecologically important ecosystems within a region. Careful attention is put toward the representativeness of a site for a certain area and usually within as structurally and functionally homogeneous an ecosystem as possible. However, even ecosystems considered homogeneous, such as deserts, mangroves, and the Arctic tundra
terrestrialβocean interfaces, and be used for targets of opportunity (e.g., flooding, fires, and land use changes). Flux measurement sites are typically selected within predominant or ecologically important ecosystems within a region. Careful attention is put toward the representativeness of a site for a certain area and usually within as structurally and functionally homogeneous an ecosystem as possible. However, even ecosystems considered homogeneous, such as deserts, mangroves, and the Arctic tundra
A Meta-Analysis of Open-Path Eddy Covariance Observations of Apparent CO2 Flux in Cold Conditions in FLUXNET, https://doi.org/10.1016/j.agrformet.2006.07.002 . 10.1016/j.agrformet.2006.07.002 Lafleur , P. M. , and E. R. Humphreys , 2008 : Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada . Global Change Biol. , 14 , 740 β 756 , https://doi.org/10.1111/j.1365-2486.2007.01529.x . 10.1111/j.1365-2486.2007.01529.x Liu , R. , Y. Li , and Q. X. Wang , 2012 : Variations in water and CO 2 fluxes over a saline desert in western China . Hydrol. Processes , 26
, https://doi.org/10.1016/j.agrformet.2006.07.002 . 10.1016/j.agrformet.2006.07.002 Lafleur , P. M. , and E. R. Humphreys , 2008 : Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada . Global Change Biol. , 14 , 740 β 756 , https://doi.org/10.1111/j.1365-2486.2007.01529.x . 10.1111/j.1365-2486.2007.01529.x Liu , R. , Y. Li , and Q. X. Wang , 2012 : Variations in water and CO 2 fluxes over a saline desert in western China . Hydrol. Processes , 26
. Anal. Chem. , 77 , 6989 β 6998 . Sylva, S. P. , Ball L. , Nelson R. K. , and Reddy C. M. , 2007 : Compound-specific 81Br/79Br analysis by capillary gas chromatography/multicollector inductively coupled plasma mass spectrometry . Rapid Commun. Mass Spectrom. , 21 , 3301 β 3305 . Teh, Y. A. , Mazeas O. , Atwood A. R. , Abel T. , and Rhew R. C. , 2009 : Hydrologic regulation of gross methyl chloride and methyl bromide uptake from Alaskan Arctic tundra . Global Change Biol
. Anal. Chem. , 77 , 6989 β 6998 . Sylva, S. P. , Ball L. , Nelson R. K. , and Reddy C. M. , 2007 : Compound-specific 81Br/79Br analysis by capillary gas chromatography/multicollector inductively coupled plasma mass spectrometry . Rapid Commun. Mass Spectrom. , 21 , 3301 β 3305 . Teh, Y. A. , Mazeas O. , Atwood A. R. , Abel T. , and Rhew R. C. , 2009 : Hydrologic regulation of gross methyl chloride and methyl bromide uptake from Alaskan Arctic tundra . Global Change Biol
Performance Evaluation of an Integrated Open-Path Eddy Covariance System in a Cold Desert Environment, 23803 , doi: 10.3402/tellusb.v66.23803 . Lafleur, P. M. , and Humphreys E. R. , 2008 : Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada . Global Change Biol. , 14 , 740 β 756 , doi: 10.1111/j.1365-2486.2007.01529.x . Lee, X. , and Massman W. , 2011 : A perspective on thirty years of the Webb, Pearman and Leuning density corrections . Bound.-Layer Meteor. , 139 , 37 β 59 , doi: 10.1007/s10546-010-9575-z . Lee, X. , Finnigan K. T. , and Paw U K. T
, 23803 , doi: 10.3402/tellusb.v66.23803 . Lafleur, P. M. , and Humphreys E. R. , 2008 : Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada . Global Change Biol. , 14 , 740 β 756 , doi: 10.1111/j.1365-2486.2007.01529.x . Lee, X. , and Massman W. , 2011 : A perspective on thirty years of the Webb, Pearman and Leuning density corrections . Bound.-Layer Meteor. , 139 , 37 β 59 , doi: 10.1007/s10546-010-9575-z . Lee, X. , Finnigan K. T. , and Paw U K. T
An In-Depth Evaluation of Heritage Algorithms for Snow Cover and Snow Depth Using AMSR-E and AMSR2 Measurementsas references in large-area assessments of microwave-derived SCA. This result is in agreement with Brown et al.βs (2010) study, which showed less than 10% of monthly difference in SCA between 4- and 24-km IMS data over the Arctic region. Fig . 7. Monthly accuracy and error difference between AMSR-E vs 24-km IMS and AMSR-E vs 4-km IMS SCA: (a) including wet snow cases and (b) excluding wet snow. A sample of 5 days (13β17) in each month between March 2004 and September 2011 is selected. The
as references in large-area assessments of microwave-derived SCA. This result is in agreement with Brown et al.βs (2010) study, which showed less than 10% of monthly difference in SCA between 4- and 24-km IMS data over the Arctic region. Fig . 7. Monthly accuracy and error difference between AMSR-E vs 24-km IMS and AMSR-E vs 4-km IMS SCA: (a) including wet snow cases and (b) excluding wet snow. A sample of 5 days (13β17) in each month between March 2004 and September 2011 is selected. The
Intercomparison of Mixing Layer Heights from the National Weather Service Ceilometer Test Sites and Collocated Radiosondes(NSA) campus is located at Barrow, Alaska (now known as UtqiaΔ‘vik; 71.323Β°N, β156.616Β°E), near sea level along the coast of the Beaufort Sea. It has mild tundra climate conditions with annual precipitation totals of 4.53 in. It is the northernmost city of the United States and is dominated by maritime polar, continental polar, and continental arctic air masses. The NSAβs ceilometer backscatter and Vaisala model RS92-SGP radiosounding data were used here from January 2013 to December 2016. The
(NSA) campus is located at Barrow, Alaska (now known as UtqiaΔ‘vik; 71.323Β°N, β156.616Β°E), near sea level along the coast of the Beaufort Sea. It has mild tundra climate conditions with annual precipitation totals of 4.53 in. It is the northernmost city of the United States and is dominated by maritime polar, continental polar, and continental arctic air masses. The NSAβs ceilometer backscatter and Vaisala model RS92-SGP radiosounding data were used here from January 2013 to December 2016. The
in stably stratified shear flow in the upper troposphere: Analysis of aircraft measurements . J. Atmos. Sci. , 64 , 2521 β 2539 . Zulueta, R. C. , Oechel W. C. , Loescher H. W. , Lawrence W. T. , and Paw U K. T. , 2011 : Aircraft-derived regional scale CO 2 fluxes from vegetated drained thaw-lake basins and interstitial tundra on the Arctic coastal plain of Alaska. Global Change Biol., 17, 2781β2802, doi:10.1111/j.1365-2486.2011.02433.x . 1 For the βBATβ scheme with the BAT
in stably stratified shear flow in the upper troposphere: Analysis of aircraft measurements . J. Atmos. Sci. , 64 , 2521 β 2539 . Zulueta, R. C. , Oechel W. C. , Loescher H. W. , Lawrence W. T. , and Paw U K. T. , 2011 : Aircraft-derived regional scale CO 2 fluxes from vegetated drained thaw-lake basins and interstitial tundra on the Arctic coastal plain of Alaska. Global Change Biol., 17, 2781β2802, doi:10.1111/j.1365-2486.2011.02433.x . 1 For the βBATβ scheme with the BAT
