Inferring Cirrus Size Distributions through Satellite Remote Sensing and Microphysical Databases

2010 ◽  
Vol 67 (4) ◽  
pp. 1106-1125 ◽  
Author(s):  
David L. Mitchell ◽  
Robert P. d’Entremont ◽  
R. Paul Lawson
Keyword(s):  
Climate Models ◽  
Relative Concentration ◽  
In Situ Measurements ◽  
Ice Crystals ◽  
Effective Diameter ◽  
Microphysical Properties ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract Since cirrus clouds have a substantial influence on the global energy balance that depends on their microphysical properties, climate models should strive to realistically characterize the cirrus ice particle size distribution (PSD), at least in a climatological sense. To date, the airborne in situ measurements of the cirrus PSD have contained large uncertainties due to errors in measuring small ice crystals (D ≲ 60 μm). This paper presents a method to remotely estimate the concentration of the small ice crystals relative to the larger ones using the 11- and 12-μm channels aboard several satellites. By understanding the underlying physics producing the emissivity difference between these channels, this emissivity difference can be used to infer the relative concentration of small ice crystals. This is facilitated by enlisting temperature-dependent characterizations of the PSD (i.e., PSD schemes) based on in situ measurements. An average cirrus emissivity relationship between 12 and 11 μm is developed here using the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument and is used to “retrieve” the PSD based on six different PSD schemes. The PSDs from the measurement-based PSD schemes are compared with corresponding retrieved PSDs to evaluate differences in small ice crystal concentrations. The retrieved PSDs generally had lower concentrations of small ice particles, with total number concentration independent of temperature. In addition, the temperature dependence of the PSD effective diameter De and fall speed Vf for these retrieved PSD schemes exhibited less variability relative to the unmodified PSD schemes. The reduced variability in the retrieved De and Vf was attributed to the lower concentrations of small ice crystals in the retrieved PSD.

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 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.

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 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.

scholarly journals Northern Hemisphere Contrail Properties Derived from Terra and Aqua MODIS Data for 2006 and 2012

2018 ◽  
Author(s):  
David P. Duda ◽  
Sarah T. Bedka ◽  
Patrick Minnis ◽  
Douglas Spangenberg ◽  
Konstantin Khlopenkov ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Radiative Forcing ◽  
Detection Algorithm ◽  
Air Traffic ◽  
Effective Diameter ◽  
Spreading Factor ◽  
Modis Imagery ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. Linear contrail coverage, optical property, and radiative forcing data over the Northern Hemisphere (NH) are derived from a year (2012) of Terra and Aqua Moderate-resolution Imaging Spectroradiometer (MODIS) imagery, and are compared with previously published 2006 results (Duda et al., 2013; Bedka et al., 2013; Spangenberg et al., 2013) using a consistent retrieval methodology. Differences in the observed Terra-minus-Aqua screened contrail coverage and patterns in the 2012 annual-mean air traffic estimated with respect to satellite overpass time suggest that most contrails detected by the contrail detection algorithm (CDA) form approximately 2 h before overpass time. The 2012 screened NH contrail coverage (Mask B) shows a relative 3 % increase (from 0.136 % to 0.140 %) compared to 2006 data for Terra and increased by almost 7 % (0.134 % to 0.143 %) for Aqua. A new post-processing algorithm added to the contrail mask processing estimated that the total contrail cirrus coverage visible in the MODIS imagery may be three to four times larger than the linear contrail coverage detected by the CDA. This estimate is similar in magnitude to the spreading factor estimated by Minnis et al. (2013). Contrail property retrievals of the 2012 data indicate that both contrail optical depth and contrail effective diameter decreased approximately 10 % between 2006 and 2012. The decreases may be attributed to better background cloudiness characterization, changes in the waypoint screening, or changes in contrail temperature. The total mean contrail radiative forcing (TCRF) for all 2012 Terra observations were −6.3, 14.3, and 8.0 mW m−2 for the shortwave (SWCRF), longwave (LWCRF), and net forcings, respectively. These values are approximately 20 % less than the corresponding 2006 Terra estimates. The decline in TCRF results from the decrease in normalized CRF, partially offset by the 3 % increase in overall contrail coverage in 2012. The TCRFs for 2012 Aqua are similar, −6.4, 15.5, and 9.0 mW m−2 for shortwave, longwave, and net radiative forcing. The strong correlation between the relative changes in both total SWCRF and LWCRF between 2006 and 2012 and the corresponding relative changes in screened contrail coverage over each air traffic region suggests that regional changes in TCRF from year to year are dominated by interannual changes in contrail coverage over each area.

Sign in / Sign up

Export Citation Format

Share Document