Clear-Sky Composites over Canada from Visible Infrared Imaging Radiometer Suite: Continuing MODIS Time Series into the Future

The Visible Infrared Imaging Radiometer Suite (VIIRS) represents a new generation of satellite imagers for global operational observations. In many aspects, it is comparable to the Moderate Resolution Imaging Spectroradiometer (MODIS) operated since 2000, i.e. almost for two decades. The Canada Centre for Remote Sensing has developed a unique MODIS processing chain to produce a long-term time series of clear-sky composites and some terrestrial products at 250 m spatial resolution over a 5700 km × 4800 km region centered on Canada. The paper describes an extension of the MODIS time series at the top of the atmosphere level using VIIRS data. The VIIRS clear-sky composites are produced on a 250-m spatial grid for I-bands and a 500-m grid for M-bands. Nominal products are generated as 10-day composites, while snow mask and normalized difference vegetation index are generated as daily products. Preliminary assessment of VIIRS versus MODIS composites has been conducted through comparison of value-added warm season snow/ice probability maps and minimum snow/ice extent. The results demonstrate a high level of consistency (with the average different difference around 0.12%), which indicates that the developed VIIRS processing technology produces results that can potentially be used to extend MODIS time series into the future

Landfast Ice Mapping Using MODIS Clear-Sky Composites: Application for the Banks Island Coastline in Beaufort Sea and Comparison with Canadian Ice Service Data

Landfast ice (LFI) is a prominent climatological feature in the Canadian Arctic. LFI is generally defined as immobile near-shore ice that remains fast along the coast and forms seaward from the land. It affects the coastline dynamics, is important for the near-shore ecosystems, wildlife, and human socio-economic activities. A method is proposed for mapping the LFI using time series of 10-day clear-sky composites derived at the Canada Center for Remote Sensing (CCRS) from the Moderate Resolution Imaging Spectroradiometer (MODIS) 250-m imagery. The delineation of coastal zone ice utilizes simultaneous analysis of the mean and standard deviation of MODIS monthly reflectance maps. The application of this method is demonstrated for a 20-year period (2000–2019) over the coastal zone of Banks Island in the Beaufort Sea. Detailed analyses have been conducted for three LFI parameters: (1) the total area (spatial extent) occupied by LFI; (2) the distance from the coast to the outer seaward LFI edge, and (3) the water depth at the outer seaward LFI edge. Comparison with the Canadian Ice Service (CIS) data demonstrates good agreement. The average correlation coefficients between CIS and CCRS time series in April-June, when the area reaches a maximum, are equal to 0.87–0.88. The mean differences (CIS-CCRS) are 344 km2 (5,464 km2 vs 5,120 km2) or 6.3% for the spatial extent; 1.3 km (17.6 km vs 16.3 km) or 7.4% for the distance; −2.7 m (−27.4 m vs −24.7 m) or 10% for the water depth. Because the CCRS method uses monthly statistics, it tends to exclude potentially more mobile continuous landfast ice zones than the CIS analysis which is based on data collected on a specific date. The long-term trends of the LFI seasonal cycle in our region of interest since 2000 have shown a tendency for an earlier break-up, later onset, and longer ice-free period; however, these trends are not statistically significant

Removal of systematic seasonal atmospheric signal from interferometric synthetic aperture radar ground deformation time series

Applying the Multidimensional Small Baseline Subset interferometric synthetic aperture radar algorithm to about 1500 Envisat and RADARSAT-2 interferograms spanning 2003–2013, we computed time series of ground deformation over Naples Bay Area in Italy. Two active volcanoes, Vesuvius and Campi Flegrei, are located in this area in close proximity to the densely populated city of Naples. For the first time, and with remarkable clarity, we observed decade-long elevation-dependent seasonal oscillations of the vertical displacement component with a peak-to-peak amplitude of up to 3.0 cm, substantially larger than the long-term deformation rate (<0.6 cm/yr). Analysis, utilizing surface weather and radiosonde data, linked observed oscillations with seasonal fluctuations of water vapor, air pressure, and temperature in the lower troposphere. The modeled correction is in a good agreement with observed results. The mean, absolute, and RMS differences are 0.014 cm, 0.073 cm, and 0.087 cm, respectively. Atmospherically corrected time series confirmed continuing subsidence at Vesuvius previously observed by geodetic techniques.Peer reviewe

Landfast ice properties over the Beaufort Sea region in 2000-2019 from MODIS and Canadian Ice Service data

Two decades (2000-2019) of the landfast ice properties in the Beaufort Sea region in the Canadian Arctic were analyzed at 250-m spatial resolution from two sources: 1) monthly maps derived at the Canada Centre for Remote Sensing from the Moderate Resolution Imaging Spectroradiometer clear-sky satellite image composites; 2) Canadian Ice Service charts. Detailed comparisons have been conducted for the landfast ice spatial extent, the water depth at and the distance to the outer seaward edge from the coast in four sub-regions: 1) Alaska coast; 2) Barter Island to Herschel Island; 3) Mackenzie Bay; 4) Richards Island to Cape Bathurst. The results from both sources demonstrate good agreement. The average spatial extent for the entire region over the April-June period is 48.5 (5.0)10The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Final report for the project "Improving the understanding of surface-atmosphere radiative interactions by mapping surface reflectance over the ARM CART site" (award DE-FG02-02ER63351)

Surface spectral reflectance (albedo) is a fundamental variable affecting the transfer of solar radiation and the Earth’s climate. It determines the proportion of solar energy absorbed by the surface and reflected back to the atmosphere. The International Panel on Climate Change (IPCC) identified surface albedo among key factors influencing climate radiative forcing. Accurate knowledge of surface reflective properties is important for advancing weather forecasting and climate change impact studies. It is also important for determining radiative impact and acceptable levels of greenhouse gases in the atmosphere, which makes this work strongly linked to major scientific objectives of the Climate Change Research Division (CCRD) and Atmospheric Radiation Measurement (ARM) Program. Most significant accomplishments of eth project are listed below. I) Surface albedo/BRDF datasets from 1995 to the end of 2004 have been produced. They were made available to the ARM community and other interested users through the CCRS public ftp site ftp://ftp.ccrs.nrcan.gc.ca/ad/CCRS_ARM/ and ARM IOP data archive under “PI data Trishchenko”. II) Surface albedo properties over the ARM SGP area have been described for 10-year period. Comparison with ECMWF data product showed some deficiencies in the ECMWF surface scheme, such as missing some seasonal variability and no dependence on sky-conditions which biases surface energy budget and has some influence of the diurnal cycle of upward radiation and atmospheric absorption. III) Four surface albedo Intensive Observation Period (IOP) Field Campaigns have been conducted for every season (August, 2002, May 2003, February 2004 and October 2004). Data have been prepared, documented and transferred to ARM IOP archive. Nine peer-reviewed journal papers and 26 conference papers have been published

The Atmospheric Imaging Mission for Northern Regions: AIM-North

AIM-North is a proposed satellite mission that would provide observations of unprecedented frequency and density for monitoring northern greenhouse gases (GHGs), air quality (AQ) and vegetation. AIM-North would consist of two satellites in a highly elliptical orbit formation, observing over land from ∼40°N to 80°N multiple times per day. Each satellite would carry a near-infrared to shortwave infrared imaging spectrometer for CO2, CH4, and CO, and an ultraviolet-visible imaging spectrometer for air quality. Both instruments would measure solar-induced fluorescence from vegetation. A cloud imager would make near-real-time observations, which could inform the pointing of the other instruments to focus only on the clearest regions. Multiple geostationary (GEO) AQ and GHG satellites are planned for the 2020s, but they will lack coverage of northern regions like the Arctic. AIM-North would address this gap with quasi-geostationary observations of the North and overlap with GEO coverage to facilitate intercomparison and fusion of these datasets. The resulting data would improve our ability to forecast northern air quality and quantify fluxes of GHG and AQ species from forests, permafrost, biomass burning and anthropogenic activity, furthering our scientific understanding of these processes and supporting environmental policy