This mosaic is calculated over the North American domain with a horizontal spatial resolution of 1 km. This mosaic therefore includes all the Canadian and American radars available in the network and which can reach a maximum of 180 contributing radars. To better represent precipitation over the different seasons, this mosaic renders in mm/h to represent rain and in cm/h to represent snow. For the two precipitation types (rain and snow), we use two different mathematical relationships to convert the reflectivity by rainfall rates (mm/h rain cm/h for snow). This is a hybrid mosaic from DPQPE (Dual-Pol Quantitative Precipitation Estimation) for S-Band radars. For the US Nexrad radars, ECCC uses the most similar product from the US Meteorological Service (NOAA). This product displays radar reflectivity converted into precipitation rates, using the same formulas as the Canadian radars.

Radar coverage is provided to dynamically display the zones covered by the radars every 6 minutes, and to provide information on the availability (or not) of the contributing radars as well as on the areas of overlap.

The Canada Centre for Mapping and Earth Observation (CCMEO) has created a 30m resolution radar mosaic of Canada's landmass from the RADARSAT Constellation Mission (RCM). This product highlights different types of radar interaction with the surface, which can assist the interpretation and study of land cover on a national scale. The national mosaic is made up of 3222 RCM images acquired between August 2023 and February 2024. (Credit: RADARSAT Constellation Mission imagery © Government of Canada [2024]. RADARSAT is an official mark of the CSA.)

The Ontario Radar DSM has the following features: * source data: 1 arc second spaceborne C-Band Interferometric Synthetic Aperture Radar (IFSAR) data * MNR Lambert Conformal Conic Projection * vertical datum in both EGM96 and CGVD28, separately * elevation value: floating * local Polynomial Interpolation from vector elevation points * spatial resolution: 30 meter * asurface elevation model This product offers significant advancements in elevation data in the province. [Read the details about these advancements and other technical specifications,](https://geohub.lio.gov.on.ca/maps/mnrf::ontario-radar-digital-surface-model/) including data processing, major spatial characteristics of the Radar DSM, and the steps to generate the Northern Ontario Radar DSM. *[MNR]: Ministry of Natural Resources *[DSM]: Digital Surface Model

This product is a 1km resolution composite over the North American domain, which, for areas with radar coverage, can distinguish the occurrence, type and intensity of precipitation. This product uses two 1km radar composites as input: a North American composite cleaned using dual polarization technology, another particle classification radar composite (precipitation) and surface temperature from the High Resolution Deterministic Prediction System (HRDPS). The SPTP product is produced every 6 minutes.

This product shows the rain accumulation, in mm, over the last 24 hour period based on DPQPE. This product is available every 6 minutes.

The three-satellite RADARSAT Constellation Mission (RCM) acquires synthetic aperture radar data of the Earth's surface. Canadian lands and waters are tracked daily. The standardized RCM acquisition plan uses ScanSAR 30m beams with a compact polarimetric configuration and enables bimonthly monitoring of Canadian land cover. The Canada Centre for Remote Sensing (CCRS) has created a 30m resolution land cover map of Canada, representing the decomposition of information from the data collected according to the type of interaction of the radar wave with the earth's surface. **This third party metadata element follows the Spatio Temporal Asset Catalog (STAC) specification.**

This data publication contains an optimized mosaic of PALSAR-2 L-band dual-polarized radar backscatter summer composite for the year 2020 across Canada (excluding the Arctic Archipelago). Its primary purpose is to offer the best possible L-band radar summer-like composite mosaic mostly tailored for i) classifying natural treed or shrubby vegetation covers, and ii) estimating their structural attributes, such as height and biomass. ## Methodology:This product is based on the freely available and open dataset of yearly JAXA Global PALSAR-2/PALSAR Mosaics ver. 1 (hereafter JAXA GPM v1). They were generated by the Japanese space agency (JAXA) using PALSAR L-band synthetic aperture radar sensors aboard the Advanced Land Observing Satellites (ALOS): ALOS-2 PALSAR-2 (2015 to 2020) and ALOS PALSAR (2007 to 2010). JAXA GPM v1 provide yearly mosaics orthorectified and slope-corrected L-band HH- and HV-polarized gamma naught (γ°) backscatter amplitude with 25-m pixel size and scaled as 16-bit data (Shimada et al. 2014). JAXA GPM v1 are accessible as a Google Earth Engine image collection at https://developers.google.com/earth-engine/datasets/catalog/JAXA_ALOS_PALSAR_YEARLY_SAR.The yearly 2007 to 2020 JAXA GPM v1 dataset across Canada underwent a post-processing and compositing methodology implemented in Google Earth Engine, as detailed in Pontone et al. 2024 and summarized in a pdf “Readme” file provided with the dataset. In summary, the method involves these three steps: 1. Post-processing of yearly γ° HH and HV datasets: handling data gaps, filtering speckle noise, and generating two radar vegetation indices, the HV/HH ratio (HVHH) and the radar forest degradation index (RFDI).2. Temporal compositing from 2015 to 2020 of post-processed yearly γ° PALSAR-2 HH, HV, HVHH, and RFDI backscatter data aimed to i) address data gaps and ii) mitigate detrimental backscatter fluctuations across ALOS-2 orbits resulting from numerous out-of-summer acquisitions.3. Generating the final PALSAR-2 L-band γ° radar backscatter summer composite circa 2020 raster files. ## Performance et limitations:The resulting Canada-wide, excluding the Arctic Archipelago, gap-free and radiometrically optimized mosaic of circa 2020 PALSAR-2 L-band backscatter summer composite was found significantly improved compared to the single-year 2020 JAXA GPM v1 mosaic, particularly in northern boreal Canada (Pontone et al. 2024). However, this product should be considered as a summer-like composite and users should be mindful of the following known limitations: • In northwestern Canada, there were often minimal to no summer PALSAR-2 acquisitions, resulting in residual backscatter fluctuations across ALOS-2 orbits.• The composite may exhibit patchy radiometric noise in areas that experienced major disturbances (fires, harvesting) between 2015 and 2020 despite they were accounted for in our compositing methodology.• This product is deemed less performant, or possibly not suitable, for i) characterizing highly dynamic land cover types such as grasslands, croplands, and water bodies, or for ii) estimating soil and/or vegetation moisture content for the year 2020.As a final note, JAXA released an improved GPM ver. 2 that was not available at the time of this study. A preliminary analysis shows that the circa 2020 PALSAR-2 composite product still seems to outperform the 2020 JAXA GPM v2 in northern Canada. ## Additional Information on Dataset: This dataset comprises four raster geotiff files of circa 2020 L-band PALSAR-2 summer temporal composites as mosaics of orthorectified and radiometrically slope corrected dual-polarized HH and HV gamma naught (γ°) backscatter amplitude, along with two radar vegetation indices (HVHH, RFDI), all scaled as 16-bit Digital Number (DN) values with 30-m pixel size in Lambert conformal conic projection. An additional 8-bit RGB quick-view file is also provided. A companion pdf ”Readme” file provides further details about these geotiff files and equations to convert DN values to γ° absolute intensity values. ## Dataset Citation: Beaudoin, A., Villemaire, P., Gignac, C., Tolszczuk, S., Guindon, L., Pontone, N., Millard, C. (2024). Canada’s PALSAR-2 dual-polarized L-band radar summer backscatter composite, circa 2020. Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Quebec, Canada. https://doi.org/10.23687/8ec4ee78-9240-4bd0-9c97-d3a27829e209In addition, please provide credits to the Japanese space agency JAXA with the mention “Original Global PALSAR-2/PALSAR Mosaics v1 provided by JAXA (©JAXA)” ## Publication Reference for Product Development and Use in Wetland Mapping: Pontone, N., Millard, K., Thompson, D., Guindon, L., Beaudoin, A. (2024). A hierarchical, Multi-Sensor Framework for Peatland Sub-Class and Vegetation Mapping Throughout the Canadian Boreal Forest. Remote Sensing for Ecology and Conservation (accepted for publication).## Cited reference: Shimada, M., Itoh, T., Motooka, T., Watanabe, M., Tomohiro, S., Thapa, T., Lucas, R. (2014). New Global Forest/Non-Forest Maps from ALOS PALSAR Data (2007-2010). Remote Sensing of Environment, 155, pp. 13-31. https://doi.org/ 10.1016/j.rse.2014.04.014

The ASTER instrument that was launched onboard NASA’s Terra spacecraft in December 1999 has an along-track stereoscopic capability using two telescopes in its near infrared spectral band to acquire data from nadir and backward views. Over 1.2 million scenes (level-1A products) acquired between March 2000 and August 2008 were used to generate the ASTER Global DEM (ASTGTM) collection.  For more information, please see the metadata link above.

This dataset provides the results obtained by Health Canada’s Radiological Monitoring Network (CRMN) for airborne radioactivity content at monitoring stations across Canada. More information about the CRMN network can be found on the Health Canada website (see link below). The results provided are activity concentration, uncertainty and the minimum detectable concentration for the naturally occurring radionuclides, beryllium-7 (7Be) and lead-210 (210Pb), and the anthropogenic (originating from human activity) radionuclides, cesium-134 (134Cs), cesium-137 (137Cs), and iodine-131 (131I). The data comes from the analysis of particulates accumulated in filter media, drawn by high-volume air samplers fixed in the field. Such data is typically dominated by natural radionuclides, such as 7Be and 210Pb. 7Be is a natural cosmogenic radionuclide that is produced in the upper atmosphere when cosmic rays bombard oxygen and nitrogen. 210Pb is also a natural radioisotope that results from the decay of uranium (238U) to radium (226Ra). 238U comes from the soil and eventually decays to 210Pb. Radon-222, which is a natural radioactive gas, is also a part of this decay chain. Radon moves through the soil and becomes diluted in the atmosphere. If a home is built on soil or rocks that contain uranium, radon can seep into homes and may accumulate to high levels. More information about the Health Canada radon program can be found on the Health Canada website. For all our stations, the airborne radioactivity data shows a small increase in the activity concentration of 134Cs, 137Cs and 131I measured between March and May of 2011, attributable to the nuclear accident at the Fukushima-Daiichi Nuclear Power Station. It is important to note that, even at their respective peaks, the measured activity concentrations of 134Cs, 137Cs and 131I represent only a small fraction of typical background exposure from natural sources of radiation. Occasionally, other small increases in activity concentration of anthropogenic radionuclides are observed. Spikes in 137Cs activity are often associated with forest fires, which can lead to the re-suspension of 137Cs already present in the environment, most likely from atmospheric nuclear weapons testing in the 1960’s. Detection of small amounts of 131I is commonly associated with its medical use by hospitals.The map shows the approximate sampling location for each monitoring station. Stations are found within the associated location range.