INSAT-3D SST and its diurnal variability assessment using in-situ and MODIS observations

Even though the actual levels of anthropogenic pollution around South Eastern Europe do not reach the ones experienced in numerous Central and Western locations such as the Po Valley, the Benelux regions, the English Channel, etc., both nitrogen and sulphur oxides remain a cause for concern for air quality issues in the area. S5P/TROPOMI offers a high enough spatial resolution of 3.5x7km2 (x5.5km2 since August 2019) coupled with a high signal-to-noise to allow the monitoring of air quality levels, as well as the calculation of emissions, around the overpass time of the satellite. In that respect, LOTOS-EUROS Chemical Transport Model (CTM) simulations for year 2018 will be used in conjunction to the S5P/TROPOMI NO2 v01.03.02 and SO2 v01.01.07 columns to update the current emission inventory used in CAMS, provided recently by TNO for year 2015.The process is validated at every step; the CTM surface concentrations are being compared to the European Environmental Agency E1a & E2a in situ air quality station data while the satellite vertical columns are compared to MAX-DOAS ground-based measurements. The diurnal variability of the NO2 depicted by the in situ and the CTM is examined, as a source of understanding the effect of the apriori emission fields, the OH radical chemistry, the planetary boundary layer definition, etc., within the model structure. The seasonal variability of the SO2 columns observed by the satellite and ground-based instruments reveals the amount of insufficiently filtered power plants and smelting activities in the area, including transboundary transport around the Balkan Peninsula.Area sources, such as cities and industrial regions, as well as shipping plumes around the Aegean Sea, the Bosporus Strait and the Eastern Mediterranean, will be characterized vis-&#224;-vis their updated emissions and discussed.Acknowledgements:We acknowledge support of this work by the project &#8220;PANhellenic infrastructure for Atmospheric Composition and climatE change&#8221; (MIS 5021516) which is implemented under the Action &#8220;Reinforcement of the Research and Innovation Infrastructure&#8221;, funded by the Operational Programme "Competitiveness, Entrepreneurship and Innovation" (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund). This work was co-funded by ESA within the Contract No. 4000117151/16/l-LG &#8220;Preparation and Operations of the Mission Performance Centre (MPC) for the Copernicus Sentinel-5 Precursor Satellite&#8221;.

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Observations of seasonal and diurnal glacier velocities at Mount Rainier, Washington, using terrestrial radar interferometry

The Cryosphere ◽

10.5194/tc-9-2219-2015 ◽

2015 ◽

Vol 9 (6) ◽

pp. 2219-2235 ◽

Cited By ~ 11

Author(s):

K. E. Allstadt ◽

D. E. Shean ◽

A. Campbell ◽

M. Fahnestock ◽

S. D. Malone

Keyword(s):

Radar Interferometry ◽

Surface Velocity ◽

Spatial And Temporal Variability ◽

Diurnal Variability ◽

Alpine Glacier ◽

Mount Rainier ◽

Glacier Dynamics ◽

Central Regions

Abstract. We present surface velocity maps derived from repeat terrestrial radar interferometry (TRI) measurements and use these time series to examine seasonal and diurnal dynamics of alpine glaciers at Mount Rainier, Washington. We show that the Nisqually and Emmons glaciers have small slope-parallel velocities near the summit (< 0.2 m day−1), high velocities over their upper and central regions (1.0–1.5 m day−1), and stagnant debris-covered regions near the terminus (< 0.05 m day−1). Velocity uncertainties are as low as &pm;0.02–0.08 m day−1. We document a large seasonal velocity decrease of 0.2–0.7 m day−1 (−25 to −50 %) from July to November for most of the Nisqually Glacier, excluding the icefall, suggesting significant seasonal subglacial water storage under most of the glacier. We did not detect diurnal variability above the noise level. Simple 2-D ice flow modeling using TRI velocities suggests that sliding accounts for 91 and 99 % of the July velocity field for the Emmons and Nisqually glaciers with possible ranges of 60–97 and 93–99.5 %, respectively, when considering model uncertainty. We validate our observations against recent in situ velocity measurements and examine the long-term evolution of Nisqually Glacier dynamics through comparisons with historical velocity data. This study shows that repeat TRI measurements with > 10 km range can be used to investigate spatial and temporal variability of alpine glacier dynamics over large areas, including hazardous and inaccessible areas.

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Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-12823-2015 ◽

2015 ◽

Vol 15 (22) ◽

pp. 12823-12843 ◽

Cited By ~ 43

Author(s):

L. Zhu ◽

D. Henze ◽

J. Bash ◽

G.-R. Jeong ◽

K. Cady-Pereira ◽

...

Keyword(s):

Transport Model ◽

In Situ Measurements ◽

Global Evaluation ◽

Chemical Transport Model ◽

Southeastern China ◽

Surface Exchange ◽

Diurnal Variability ◽

Fertilizer Application Rate ◽

Bidirectional Exchange

Abstract. Bidirectional air–surface exchange of ammonia (NH3) has been neglected in many air quality models. In this study, we implement the bidirectional exchange of NH3 in the GEOS-Chem global chemical transport model. We also introduce an updated diurnal variability scheme for NH3 livestock emissions and evaluate the recently developed MASAGE_NH3 bottom-up inventory. While updated diurnal variability improves comparison of modeled-to-hourly in situ measurements in the southeastern USA, NH3 concentrations decrease throughout the globe, up to 17 ppb in India and southeastern China, with corresponding decreases in aerosol nitrate by up to 7 μg m−3. The ammonium (NH4+) soil pool in the bidirectional exchange model largely extends the NH3 lifetime in the atmosphere. Including bidirectional exchange generally increases NH3 gross emissions (7.1 %) and surface concentrations (up to 3.9 ppb) throughout the globe in July, except in India and southeastern China. In April and October, it decreases NH3 gross emissions in the Northern Hemisphere (e.g., 43.6 % in April in China) and increases NH3 gross emissions in the Southern Hemisphere. Bidirectional exchange does not largely impact NH4+ wet deposition overall. While bidirectional exchange is fundamentally a better representation of NH3 emissions from fertilizers, emissions from primary sources are still underestimated and thus significant model biases remain when compared to in situ measurements in the USA. The adjoint of bidirectional exchange has also been developed for the GEOS-Chem model and is used to investigate the sensitivity of NH3 concentrations with respect to soil pH and fertilizer application rate. This study thus lays the groundwork for future inverse modeling studies to more directly constrain these physical processes rather than tuning bulk unidirectional NH3 emissions.

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A Study of CINDY/DYNAMO MJO Suppressed Phase

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-13-0348.1 ◽

2015 ◽

Vol 72 (10) ◽

pp. 3755-3779 ◽

Cited By ~ 26

Author(s):

Sue Chen ◽

Maria Flatau ◽

Tommy G. Jensen ◽

Toshiaki Shinoda ◽

Jerome Schmidt ◽

...

Keyword(s):

Surface Temperature ◽

Sea Surface Temperature ◽

Intraseasonal Variability ◽

Precipitable Water ◽

Sea Surface ◽

Diurnal Variability ◽

Oscillatory Pattern ◽

Tightly Coupled ◽

Moisture Increase

Abstract The diurnal variability and the environmental conditions that support the moisture resurgence of MJO events observed during the Cooperative Indian Ocean Experiment on Intraseasonal Variability (CINDY)/DYNAMO campaign in October–December 2011 are investigated using in situ observations and the cloud-resolving fully air–ocean–wave Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS). Spectral density and wavelet analysis of the total precipitable water (TPW) constructed from the DYNAMO soundings and TRMM satellite precipitation reveal a deep layer of vapor resurgence during the observed Wheeler and Hendon real-time multivariate MJO index phases 5–8 (MJO suppressed phase), which include diurnal, quasi-2-, quasi-3–4-, quasi-6–8-, and quasi-16-day oscillations. A similar oscillatory pattern is found in the DYNAMO moorings sea surface temperature analysis, suggesting a tightly coupled atmosphere and ocean system during these periods. COAMPS hindcast focused on the 12–16 November 2011 event suggests that both the diurnal sea surface temperature (SST) pumping and horizontal and vertical moisture transport associated with the westward propagating mixed Rossby–Gravity (MRG) waves play an essential role in the moisture resurgence during this period. Idealized COAMPS simulations of MRG waves are used to estimate the MRG and diurnal SST contributions to the overall moisture increase. These idealized MRG sensitivity experiments showed the TPW increase varies from 9% to 13% with the largest changes occurring in the simulations that included a diurnal SST variation of 2.5°C as observed.

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Cloud droplet variability in the summertime in the southeast United States: day vs. night

10.5194/egusphere-egu21-16245 ◽

2021 ◽

Author(s):

Aikaterini Bougiatioti ◽

Athanasios Nenes ◽

Jack Lin ◽

Charles Brock ◽

Joost de Gouw ◽

...

Keyword(s):

Chemical Composition ◽

Vertical Velocity ◽

Cloud Droplet ◽

Limited Effect ◽

Southeast United States ◽

Diurnal Variability ◽

Upper Limit ◽

Velocity Changes ◽

Do So

During the 2013 Southeast Nexus (SENEX) campaign, in-situ observational data were collected on board the NOAA WP-3D aircraft to study the aerosol-cloud droplet link and examine the sensitivity of the cloud droplet number to aerosol physicochemical parameters. In order to do so, observed aerosol number size distributions, chemical composition and vertical-velocity distributions were introduced into a state-of-the-art cloud droplet parameterization from which cloud droplet number and cloud maximum supersaturations were derived. We find that the standard deviation of the vertical velocity (&#963;w) exhibits significant diurnal variability ranging from 0.16 m s-1 during nighttime to over 1.2 m s-1 during day. Total aerosol number (Na) covaries with &#963;w , with lower values observed during nighttime. The covariance between &#963;w and Na enhances the apparent response of Nd to changes in Na levels by a factor of 5. For the same &#8220;cleaner&#8221; environments where Na values are limited and not impacted by local sources, the relative response of Nd to &#963;w is almost twice as great during night, compared to the day (24% during day vs. 42% during night). On the other hand, in environment with enhanced concentrations, especially of accumulation-mode particles, the majority of droplet number variability is attributed to changes in total aerosol number rather than changes in &#963;w. Chemical composition is found to on-average have a limited effect on Nd variability (4%). Finally, we identify an upper limit to the number of droplets that can form in clouds which depends only on &#963;w independently from total aerosol number. Doubling &#963;w from 0.2 to 0.3 m s-1increases this limiting droplet number by 52%.When Nd values approach this upper limit the observed droplet variability is driven by &#963;w and, subsequently, by vertical-velocity changes only. Therefore only by using this -&#963;w relationship in regions where velocity-limited conditions are expected, &#963;w can be estimated from retrievals of droplet number and vice versa.

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Assessing the summer water budget of a moulin basin in the Sermeq Avannarleq ablation region, Greenland ice sheet

Journal of Glaciology ◽

10.3189/002214311798043735 ◽

2011 ◽

Vol 57 (205) ◽

pp. 954-964 ◽

Cited By ~ 47

Author(s):

Daniel McGrath ◽

William Colgan ◽

Konrad Steffen ◽

Phillip Lauffenburger ◽

James Balog

Keyword(s):

Water Budget ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Time Lapse ◽

Balance Model ◽

Diurnal Variability ◽

Surface Uplift ◽

Ice Surface ◽

Basal Sliding

AbstractWe provide an assessment of the supraglacial water budget of a moulin basin on the western margin of the Greenland ice sheet for 15 days in August 2009. Meltwater production, the dominant input term to the 1.14 ± 0.06 km2 basin, was determined from in situ ablation measurements. The dominant water-output terms from the basin, accounting for 52% and 48% of output, respectively, were moulin discharge and drainage into crevasses. Moulin discharge exhibits large diurnal variability (0.017–0.54 m3 s−1) with a distinct late-afternoon peak at 16:45 local time. This lags peak meltwater production by ∼2.8 ± 4.2 hours. An Extreme Ice Survey time-lapse photography sequence complements the observations of moulin discharge. We infer, from in situ observations of moulin geometry, previously published borehole water heights and estimates of the temporal lag between meltwater production and observed local ice surface uplift (‘jacking’), that the transfer of surface meltwater to the englacial water table via moulins is nearly instantaneous (<30 min). We employ a simple crevasse mass-balance model to demonstrate that crevasse drainage could significantly dampen the surface meltwater fluctuations reaching the englacial system in comparison to moulin discharge. Thus, unlike crevasses, moulins propagate meltwater pulses to the englacial system that are capable of overwhelming subglacial transmission capacity, resulting in enhanced basal sliding.

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In situ measurements of volatile organic compounds in a boreal forest

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-11665-2012 ◽

2012 ◽

Vol 12 (23) ◽

pp. 11665-11678 ◽

Cited By ~ 69

Author(s):

H. Hakola ◽

H. Hellén ◽

M. Hemmilä ◽

J. Rinne ◽

M. Kulmala

Keyword(s):

Boreal Forest ◽

Diurnal Variation ◽

Cold Trap ◽

Diurnal Variability ◽

Radical Reactivity ◽

Boundary Layer Height ◽

Mixing Ratios ◽

Biogenic Voc ◽

Biogenic Compounds

Abstract. We present biogenic VOC, including sesquiterpenes, measurements at the SMEAR II station (Station For Measuring Forest Ecosystem-Atmosphere Relations) in Finland using an in situ gas chromatograph mass-spectrometer with 2 h time resolution. The measurements were conducted over the period October 2010–October 2011, at least one week every month. To our knowledge there are no earlier species-speciated semi-continuous BVOC data also covering dormant periods. This was also the first time sesquiterpene mixing ratios were measured in a boreal forest. During the winter months, and still in March, the mixing ratios of all biogenic compounds were very low, most of the time below detection limits. The monoterpene mixing ratios increased in April and started to show diurnal variability, with maximum mixing ratio at night and minima during the day. The diurnal variability continued until October, after which the mixing ratios decreased and then only occasional episodes took place. The diurnal variation was affected by boundary layer height. Sesquiterpene mixing ratios were very low, only a few ppt. The main sesquiterpenes were longifolene and isolongifolene. The diurnal variation of isoprene was opposite to the mono- and sesquiterpene diurnal curve due to isoprene's light dependent emissions. Due to its daytime maximum mixing ratios, isoprene also dominated hydroxyl radical reactivity in summer even though our isoprene measurements are underestimates due to a breakthrough in a cold trap.

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Determination of AATSR Biases Using the OSTIA SST Analysis System and a Matchup Database

Journal of Atmospheric and Oceanic Technology ◽

10.1175/2008jtecho560.1 ◽

2008 ◽

Vol 25 (7) ◽

pp. 1208-1217 ◽

Cited By ~ 21

Author(s):

J. D. Stark ◽

C. Donlon ◽

A. O’Carroll ◽

G. Corlett

Keyword(s):

European Space Agency ◽

Pilot Project ◽

Global Ocean ◽

Bias Error ◽

Cold Bias ◽

Error Statistics ◽

Zero Bias ◽

Diurnal Variability ◽

Warm Bias

Abstract Sea surface temperature (SST) analyses are produced on a daily basis at the Met Office using the Operational SST and Sea Ice Analysis (OSTIA) system. OSTIA uses satellite SST data, provided by international agencies via the Global Ocean Data Assimilation Experiment (GODAE) High-Resolution SST Pilot Project (GHRSST-PP) regional/global task sharing (R/GTS) framework, which includes an estimate of bias error (available online at http://www.ghrsst-pp.org). The OSTIA system produces a foundation SST estimate (SSTfnd), which is the SST that is free of diurnal variability, at a resolution of 1/20° (∼6 km). Global coverage outputs are provided each day in GHRSST-PP L4 netCDF format. The verification and intercomparison of the OSTIA analysis, with observations and analyses, has revealed a cold bias of approximately 0.1 K in the OSTIA outputs. Because OSTIA uses the operational 1-km Envisat Advanced Along-Track Scanning Radiometer (AATSR) ATS_NR_2P data [via the GHRSST-PP/European Space Agency (ESA) Medspiration Project, available online at http://www.medspiration.org] as a reference dataset for bias adjustment of other satellite data, the AATSR data were identified as the likely cause of the observed bias. To test this, a series of experiments were carried out in June 2006 using the Medspiration AATSR observations in which the Single Sensor Error Statistics (SSES) bias estimate was assigned fixed magnitudes of 0.0, 0.05, 0.15, and 0.2 K. The authors find that the AATSR data have approximately zero bias relative to in situ buoys. Because AATSR measures the SST skin temperature (SSTskin) and was given a mean global SSTskin deviation of −0.17 K (based on in situ radiometer data), this result suggests that ATS_NR_2P SSTskin data have a warm bias of 0.17 K. Using a matchup database of near-contemporaneous 10 arc min AATSR and in situ data, the authors find that the AATSR SSTskin dual- and triple-window retrievals have a warm bias of 0.14 and 0.17 K, respectively, between August 2002 and July 2006. The results of the experiments confirm that the current Medspiration SSES bias correction provided with the Medspiration AATSR L2P observations is poorly specified. The database was not configured to test the relationship between the cloud proximity confidence value and the AATSR bias error. Based on the matchup database and reanalysis results, the authors suggest that Medspiration be modified to use an SSES bias estimate of 0.17 K for all category 2–6 proximity confidence values for the current AATSR dual-view SST ATS_NR_2P products to provide a correct SSTskin estimate. In response to the results presented in this study, operational changes have been made to the Medspiration processing, which improve the bias estimates provided in the AATSR data. The authors suggest that a concerted effort be invested to develop the most appropriate SSES for the AATSR class of sensors that have specific characteristics that must be included in the SSES estimation scheme. The main elements of such a scheme are presented in this paper.

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Diurnal Variation of Cell Proliferation in Three Bacterial Taxa from Coastal North Sea Waters

Applied and Environmental Microbiology ◽

10.1128/aem.71.8.4638-4644.2005 ◽

2005 ◽

Vol 71 (8) ◽

pp. 4638-4644 ◽

Cited By ~ 26

Author(s):

Annelie Pernthaler ◽

Jakob Pernthaler

Keyword(s):

Cell Proliferation ◽

North Sea ◽

Bacterial Population ◽

De Novo ◽

Expected Number ◽

Short Term ◽

Proliferating Cells ◽

Diurnal Variability ◽

Dinoflagellate Bloom

ABSTRACT Pulse-labeling with bromodeoxyuridine (BrdU) in combination with fluorescence in situ hybridization was applied to quantify the percentage of proliferating cells in coastal North Sea waters. In order to assess diurnal variability, we sampled eight or nine times, respectively, within 3 consecutive days at two seasons. Bacteria affiliated with the Roseobacter, SAR86, and NOR5 lineages constituted on average 19% ± 3%, 8% ± 2%, and 6% ± 1% of all cells in May 2002 and 17% ± 3%, 10% ± 2%, and 11% ± 3% in August. The relative abundances of the three populations either remained stable, or they changed very gradually during the observation periods. On average, 38 and 39% of all Bacteria exhibited DNA de novo synthesis in May and August, respectively. The fractions of proliferating cells in bacteria of the SAR86 (May, 59%; August, 72%) and the Roseobacter (48 and 53%) lineages were significantly above the community average. A substantial cell proliferation of population NOR5 (34%) was only encountered in August, concomitant with a dinoflagellate bloom. Significant short-term fluctuations of DNA-synthesizing cells were observed in Roseobacter during May and in NOR5 during August, hinting at a pronounced (temporal or spatial) mesoscale patchiness of growth rates in these populations. Since the BrdU proliferation assay is susceptible to misinterpretation, we also modeled the expected number of labeled cells at increasing BrdU incubation times in a slowly growing bacterial population. We suggest that the absence of visible DNA synthesis in marine bacterioplankton cells after DNA pulse-labeling must not be interpreted as an indication of cell “inactivity.”

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