The Sen2Cor [R1] processor algorithm is a combination of state-of-the-art techniques for performing atmospheric corrections which have been tailored to the Sentinel-2 environment together with a scene classification module described in [R2].
The scene classification algorithm allows detection of clouds, snow and cloud shadows and generation of a classification map, which consists of three different classes for clouds including cirrus , together with six different classifications for shadows, cloud shadows, vegetation, not vegetated, water and snow. The algorithm is based on a series of threshold tests that use as input TOA reflectance as input from the Sentinel-2 spectral bands.
For each of these threshold tests, a level of confidence is associated. It produces at the end of the processing chain a probabilistic cloud mask quality indicator and a snow mask quality indicator. The algorithm uses the reflective properties of scene features to establish the presence or absence of clouds in a scene.
Cloud screening is applied to the data in order to retrieve accurate atmospheric and surface parameters, either as input for the further processing steps below or for being valuable input for processing steps of higher levels. This algorithm requires that the scene contains reference areas of known reflectance behaviour, preferably DDV and water bodies.
The algorithm starts with a user-defined visibility default: 40 km. If the scene contains no dark vegetation or soil pixels, the surface reflectance threshold in the 2 nm band is successively iterated in order to include medium brightness reference pixels. Every five levels passed, a barrier will appear, the player will need to collect several ducks to move on.
So try to collect as many ducks as possible since retracing levels that have already been passed is time-consuming. The appearance system of the ducks has a cool superhero or a beautiful princess-like design. Swampy, Allie, or Cranky should not wait long before expressing their concerns.
Doing so causes them to scowl and turn an ugly frown. The screen will show an exclamation point whenever water, steam, or additives are wasted during play.
Thanks to the light and animated music, the players have an excellent, comfy time playing. Water or steam noises can be synthesized very well, which helps to make the game more exciting and less dull. New places, such as a soap factory or a beautiful beach, will also be found for you. To solve the puzzle levels, water, and other additives will be used. By trying things like turning on the faucets and adjusting the steam, the results could include unpredictable results.
This stage contains more difficult levels where you have to dig as quickly as possible to avoid the water from getting stuck above the screen, but you still have to collect enough ducks to finish. The levels may need to slide up or down, or no ducks must complete the game.
Not only do you get new ducks to unlock, but you also collect items and get power-ups. Return to Collection 2 Overview. Go to Collection 2 Level-1 Information.
Left: Landsat 8 Collection 2 level-1 top of atmosphere reflectance image, center: Landsat 8 Collection 2 level-2 atmospherically corrected surface reflectance image, and right: Landsat 8 Collection 2 level-2 surface temperature image for an area over the Sapta Koshi River in Bairawa, Nepal path row 41 acquired on May 3, Landsat surface temperature products are generated using the Landsat surface temperature algorithm Version 1.
Surface reflectance unitless measures the fraction of incoming solar radiation that is reflected from the Earth's surface to the Landsat sensor. Visit the Landsat Surface Reflectance webpage for additional information and documentation.
Surface temperature is also useful for monitoring crop and vegetation health, and extreme heat events such as natural disasters e. Note : A surface temperature product cannot be generated if auxiliary data is missing. Please refer to the Atmospheric Auxiliary Data and Constraints and Caveats sections on Landsat Collection 2 Surface Temperature for more specifics about the required data needed in order to create an surface temperature product.
Visit the Landsat Surface Temperature webpage for additional information and documentation. The following metadata file specifications are included in Collection 2 products to facilitate consistency, machine-to-machine scripting and rapid querying of the Landsat archive:.
Landsat Level-2 surface reflectance and surface temperature processing require atmospheric auxiliary data input from external USGS data sources.
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