scholarly journals Differences in Fine Particle Chemical Composition on Clear and Cloudy Days

2020 ◽  
Author(s):  
Amy E. Christiansen ◽  
Annmarie G. Carlton ◽  
Barron H. Henderson
Keyword(s):  
Chemical Composition ◽  
Fine Particulate Matter ◽  
The United States ◽  
Chemical Constituent ◽  
Clear Sky ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Aerosol Cloud Interactions

Abstract. Clouds are prevalent and alter fine particulate matter (PM2.5) mass and chemical composition. Cloud-affected satellite retrievals are subject to higher uncertainty and are often removed from data products, hindering quantitative estimates of tropospheric chemical composition during cloudy times. We examine surface PM2.5 chemical constituent concentrations in the Interagency Monitoring of PROtected Visual Environments (IMPROVE) network in the United States during Cloudy and Clear Sky times defined using Moderate Resolution Imaging Spectroradiometer (MODIS) cloud flags from 2010-2014 with a focus on differences in particle hygroscopicity and aerosol liquid water (ALW). Cloudy and Clear Sky periods exhibit significant differences in PM2.5 mass and chemical composition that vary regionally and seasonally. In the eastern US, relative humidity alone cannot explain differences in ALW, suggesting emissions and in situ chemistry exert determining impacts. An implicit clear sky bias may hinder efforts to quantitatively understand and improve representation of aerosol-cloud interactions, which remain dominant uncertainties in models.

scholarly journals Differences in fine particle chemical composition on clear and cloudy days

2020 ◽  
Vol 20 (19) ◽  
pp. 11607-11624
Author(s):  
Amy E. Christiansen ◽  
Annmarie G. Carlton ◽  
Barron H. Henderson
Keyword(s):  
Chemical Composition ◽  
Fine Particulate Matter ◽  
The United States ◽  
Chemical Constituent ◽  
Anthropogenic Sources ◽  
Clear Sky ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Aerosol Cloud Interactions

Abstract. Clouds are prevalent and alter fine particulate matter (PM2.5) mass and chemical composition. Cloud-affected satellite retrievals are subject to higher uncertainty and are often removed from data products, hindering quantitative estimates of tropospheric chemical composition during cloudy times. We examine surface PM2.5 chemical constituent concentrations in the Interagency Monitoring of PROtected Visual Environments (IMPROVE) network in the United States during cloudy and clear-sky times defined using Moderate Resolution Imaging Spectroradiometer (MODIS) cloud flags from 2010 to 2014 with a focus on differences in particle species that affect hygroscopicity and aerosol liquid water (ALW). Cloudy and clear-sky periods exhibit significant differences in PM2.5 mass and chemical composition that vary regionally and seasonally. In the eastern US, relative humidity alone cannot explain differences in ALW, suggesting that emissions and in situ chemistry related to anthropogenic sources exert determining impacts. An implicit clear-sky bias may hinder efforts to quantitatively understand and improve representation of aerosol–cloud interactions, which remain dominant uncertainties in models.

scholarly journals Satellite-Based Estimation of Temporally Resolved Dust Radiative Forcing in Snow Cover

2016 ◽  
Vol 17 (7) ◽  
pp. 1999-2011 ◽  
Author(s):  
Steven D. Miller ◽  
Fang Wang ◽  
Ann B. Burgess ◽  
S. McKenzie Skiles ◽  
Matthew Rogers ◽  
...  
Keyword(s):  
Solar Irradiance ◽  
Radiative Forcing ◽  
Hydrological Cycle ◽  
Clear Sky ◽  
Operational Management ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Sky Conditions

Abstract Runoff from mountain snowpack is an important freshwater supply for many parts of the world. The deposition of aeolian dust on snow decreases snow albedo and increases the absorption of solar irradiance. This absorption accelerates melting, impacting the regional hydrological cycle in terms of timing and magnitude of runoff. The Moderate Resolution Imaging Spectroradiometer (MODIS) Dust Radiative Forcing in Snow (MODDRFS) satellite product allows estimation of the instantaneous (at time of satellite overpass) surface radiative forcing caused by dust. While such snapshots are useful, energy balance modeling requires temporally resolved radiative forcing to represent energy fluxes to the snowpack, as modulated primarily by varying cloud cover. Here, the instantaneous MODDRFS estimate is used as a tie point to calculate temporally resolved surface radiative forcing. Dust radiative forcing scenarios were considered for 1) clear-sky conditions and 2) all-sky conditions using satellite-based cloud observations. Comparisons against in situ stations in the Rocky Mountains show that accounting for the temporally resolved all-sky solar irradiance via satellite retrievals yields a more representative time series of dust radiative effects compared to the clear-sky assumption. The modeled impact of dust on enhanced snowmelt was found to be significant, accounting for nearly 50% of the total melt at the more contaminated station sites. The algorithm is applicable to regional basins worldwide, bearing relevance to both climate process research and the operational management of water resources.

Test of a Modified Infrared-Only ABI Cloud Mask Algorithm for AHI Radiance Observations

2016 ◽  
Vol 55 (11) ◽  
pp. 2529-2546 ◽  
Author(s):  
X. Zhuge ◽  
X. Zou
Keyword(s):  
Near Infrared ◽  
Extended System ◽  
Clear Sky ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Cloud Mask ◽  
Very High ◽  
Lower False Alarm Rate ◽  
Infrared Channel

AbstractAssimilation of infrared channel radiances from geostationary imagers requires an algorithm that can separate cloudy radiances from clear-sky ones. An infrared-only cloud mask (CM) algorithm has been developed using the Advanced Himawari Imager (AHI) radiance observations. It consists of a new CM test for optically thin clouds, two modified Advanced Baseline Imager (ABI) CM tests, and seven other ABI CM tests. These 10 CM tests are used to generate composite CMs for AHI data, which are validated by using the Moderate Resolution Imaging Spectroradiometer (MODIS) CMs. It is shown that the probability of correct typing (PCT) of the new CM algorithm over ocean and over land is 89.73% and 90.30%, respectively and that the corresponding leakage rates (LR) are 6.11% and 4.21%, respectively. The new infrared-only CM algorithm achieves a higher PCT and a lower false-alarm rate (FAR) over ocean than does the Clouds from the Advanced Very High Resolution Radiometer (AVHRR) Extended System (CLAVR-x), which uses not only the infrared channels but also visible and near-infrared channels. A slightly higher FAR of 7.92% and LR of 6.18% occurred over land during daytime. This result requires further investigation.

scholarly journals Snow Albedo Seasonality and Trend from MODIS Sensor and Ground Data at Johnsons Glacier, Livingston Island, Maritime Antarctica

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3569
Author(s):  
Calleja ◽  
Corbea-Pérez ◽  
Fernández ◽  
Recondo ◽  
Peón ◽  
...  
Keyword(s):  
Moving Average ◽  
Data Sets ◽  
Snow Albedo ◽  
Livingston Island ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Sky Conditions ◽  
Cloud Mask

The aim of this work is to investigate whether snow albedo seasonality and trend under all sky conditions at Johnsons Glacier (Livingston Island, Antarctica) can be tracked using the Moderate Resolution Imaging Spectroradiometer (MODIS) snow albedo daily product MOD10A1. The time span is from December 2006 to February 2015. As the MOD10A1 snow albedo product has never been used in Antarctica before, we also assess the performance for the MOD10A1 cloud mask. The motivation for this work is the need for a description of snow albedo under all sky conditions (including overcast days) using satellite data with mid-spatial resolution. In-situ albedo was filtered with a 5-day windowed moving average, while the MOD10A1 data were filtered using a maximum filter. Both in-situ and MOD10A1 data follow an exponential decay during the melting season, with a maximum decay of 0.049/0.094 day−1 (in-situ/MOD10A1) for the 2006–2007 season and a minimum of 0.016/0.016 day−1 for the 2009–2010 season. The duration of the decay varies from 85 days (2007–2008) to 167 days (2013–2014). Regarding the albedo trend, both data sets exhibit a slight increase of albedo, which may be explained by an increase of snowfall along with a decrease of snowmelt in the study area. Annual albedo increases of 0.2% and 0.7% are obtained for in-situ and MOD10A1 data, respectively, which amount to respective increases of 2% and 6% in the period 2006–2015. We conclude that MOD10A1 can be used to characterize snow albedo seasonality and trend on Livingston Island when filtered with a maximum filter.

scholarly journals Seguimiento satelital de las condiciones océano-atmosféricas asociadas a los eventos de precipitación en Colombia durante el evento La Niña 2010–2011

2014 ◽  
pp. 123-134
Author(s):  
Martha Lucero Bastidas Salamanca ◽  
Apolinar Figueroa Casas
Keyword(s):  
La Niña ◽  
La Nina ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
La Niña 2010

La comprensión de la variabilidad climática es un tema de gran interés científico debido a que puede repercutir en las condiciones ambientales y socio-económicas de un país. Este estudio hace uso de datos satelitales para describir los eventos de precipitación ocurridos en el territorio colombiano durante el evento de La Niña 2010-2011 y registrados en estaciones meteorológicas costeras del Caribe. Se utilizaron datos de la temperatura de brillo de las nubes, medida por el Geostationary Operational Envirormental Satellite -GOES-12; datos de temperatura superficial del mar derivados de imágenes mensuales del Moderate Resolution Imaging Spectroradiometer – MODIS, y datos de precipitación intisituto de dos estaciones meteorológicas costeras (Cartagena y Santa Marta). Las imágenes satelitales GOES permitieron describir el evento La Niña 2010-2011 a partir de la identificación de nubes altas y complejos convectivos de mesoescala, los cuales se asocian a elevadas precipitaciones; mientras que las imágenes MODIS evidenciaron un comportamiento oceánico opuesto entre el Caribe colombiano, que exhibió anomalías positivas, y el Pacífico Oriental Tropical, que experimentó la influencia del evento y lo reflejó en anomalías negativas. Modelos lineales empleando datos satelitales de temperatura superficial del mar, in situ de precipitación y del Índice de Oscilación del Sur, revelaron que solamente para la estación ubicada en El Rodadero (Santa Marta), la precipitación fue explicada por la temperatura superficial del mar adyacente, mientras que el IOS no resultó significativo.

scholarly journals US particulate matter air quality improves except in wildfire-prone areas

2018 ◽  
Vol 115 (31) ◽  
pp. 7901-7906 ◽  
Author(s):  
Crystal D. McClure ◽  
Daniel A. Jaffe
Keyword(s):  
United States ◽  
Particulate Matter ◽  
Fine Particulate Matter ◽  
The United States ◽  
Total Carbon ◽  
Positive Trend ◽  
Modis Aod ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Using Data

Using data from rural monitoring sites across the contiguous United States, we evaluated fine particulate matter (PM2.5) trends for 1988–2016. We calculate trends in the policy-relevant 98th quantile of PM2.5 using Quantile Regression. We use Kriging and Gaussian Geostatistical Simulations to interpolate trends between observed data points. Overall, we found positive trends in 98th quantile PM2.5 at sites within the Northwest United States (average 0.21 ± 0.12 µg·m−3·y−1; ±95% confidence interval). This was in contrast with sites throughout the rest of country, which showed a negative trend in 98th quantile PM2.5, likely due to reductions in anthropogenic emissions (average −0.66 ± 0.10 µg·m−3·y−1). The positive trend in 98th quantile PM2.5 is due to wildfire activity and was supported by positive trends in total carbon and no trend in sulfate across the Northwest. We also evaluated daily moderate resolution imaging spectroradiometer (MODIS) aerosol optical depth (AOD) for 2002–2017 throughout the United States to compare with ground-based trends. For both Interagency Monitoring of Protected Visual Environments (IMPROVE) PM2.5 and MODIS AOD datasets, we found positive 98th quantile trends in the Northwest (1.77 ± 0.68% and 2.12 ± 0.81% per year, respectively) through 2016. The trend in Northwest AOD is even greater if data for the high-fire year of 2017 are included. These results indicate a decrease in PM2.5 over most of the country but a positive trend in the 98th quantile PM2.5 across the Northwest due to wildfires.

scholarly journals Sediment plumes as a proxy for local ice-sheet runoff in Kangerlussuaq Fjord, West Greenland

2010 ◽  
Vol 56 (199) ◽  
pp. 813-821 ◽  
Author(s):  
Daniel McGrath ◽  
Konrad Steffen ◽  
Irina Overeem ◽  
Sebastian H. Mernild ◽  
Bent Hasholt ◽  
...  
Keyword(s):  
River Discharge ◽  
Water Storage ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
West Greenland ◽  
Meltwater Runoff ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

AbstractMeltwater runoff is an important component of the mass balance of the Greenland ice sheet (GrIS) and contributes to eustatic sea-level rise. In situ measurements of river runoff at the ˜325 outlets are nonexistent due to logistical difficulties. We develop a novel methodology using satellite observations of sediment plumes as a proxy for the onset, duration and volume of meltwater runoff from a basin of the GrIS. Sediment plumes integrate numerous poorly constrained processes, including meltwater refreezing and supra- and englacial water storage, and are formed by meltwater that exits the GrIS and enters the ocean. Plume characteristics are measured in Moderate Resolution Imaging Spectroradiometer (MODIS, band 1, 250 m) satellite imagery during the 2001-08 melt seasons. Plume formation and cessation in Kangerlussuaq Fjord, West Greenland, are positively correlated (r2 = 0.88, n = 5, p < 0.05; r2 = 0.93, n = 5, p < 0.05) with ablation onset and cessation at the Kangerlussuaq Transect automatic weather station S5 (490 ma.s.l., 6 km from the ice margin). Plume length is positively correlated (r2 = 0.52, n = 35, p < 0.05) with observed 4 day mean Watson River discharge throughout the 2007 and 2008 melt seasons. Plume length is used to infer instantaneous and annual cumulative Watson River discharge between 2001 and 2008. Reconstructed cumulative discharge values overestimate observed cumulative discharge values for 2007 and 2008 by 15% and 29%, respectively.

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