How is cloudy is my Sentinel-2 image collection?

How is cloudy is my Sentinel-2 image collection?

In Google Earth Engine we usually load an image collection first and then filter it by a date range, a region of interest and a image property with some cloud percentage estimates. If the cloud threshold value is set too low it may happen that we throw away (filter out) to many images that could have been useful for our analysis.

How to get the least cloudy image in Google Earth?

For example, by inspecting the image objects in the printed image collections, you may have observed a metadata property called CLOUD_COVER. You can use that property to get the least cloudy image in 2015 in your area of interest: // This will sort from least to most cloudy. // Get the first (least cloudy) image.

How to do cloud masking in Google Earth?

# Subset the cloudmask band and invert it so clouds/shadow are 0, else 1. # Subset reflectance bands and update their masks, return the result. Add cloud and cloud shadow component bands to each image and then apply the mask to each image.

How are Sentinel-2 surface reflectance and cloud probability different?

Sentinel-2 surface reflectance and Sentinel-2 cloud probability are two different image collections. Each collection must be filtered similarly (e.g., by date and bounds) and then the two filtered collections must be joined.

What is the ID of the Sentinel-2 satellite?

The ID contains the Sentinel-2 satellite, start date and time, absolute orbit number, and processing baseline. The use of Sentinel data is governed by the Copernicus Sentinel Data Terms and Conditions.

How many QA bands are there in Sentinel-2?

The Sentinel-2 data contain 13 UINT16 spectral bands representing TOA reflectance scaled by 10000. See the Sentinel-2 User Handbook for details. In addition, three QA bands are present where one (QA60) is a bitmask band with cloud mask information. For more details, see the full explanation of how cloud masks are computed.

Are there any cloud detection algorithms like Sentinel-2?

Many existing cloud detection algorithms rely on temperature information to identify clouds, making detection difficult for imagers that lack a thermal band, like Sentinel-2. To get maximum benefit from Sentinel-2 products it is critical to understand which algorithms best identify clouds and their shadows in images.

What does the qa60 stand for in Sentinel-2?

Finding a good threshold is not easy, this blog post may help to find it. Each Sentinel-2 image has a bitmask band with cloud mask information – QA60. QA stands for quality while the 60 reveals the spatial resolution in meter. See the full explanation of how cloud masks are computed.

How are cloud detection algorithms used in satellite imagery?

Accurate, automated cloud and cloud shadow detection is a key component of the processing needed to prepare optical satellite imagery for scientific analysis. Many existing cloud detection algorithms rely on temperature information to identify clouds, making detection difficult for imagers that lack a thermal band, like Sentinel-2.

What’s the upper limit for cloud coverage in Sentinel-2?

Sets the upper limit for cloud coverage in percent based on the precomputed cloud coverage estimate for each Sentinel-2 tile as present in the tile metadata. Satellite data will therefore not be retrieved for tiles with a higher cloud coverage estimate.

Are there clouds in the sky with Sentinel Hub?

Sentinel-2 image from 2017–12–15 via Sentinel Hub with a cloud mask produced with the Sentinel Hub Cloud Detector at three different zoom levels. This is a story about clouds. Real clouds in the sky. Sometimes you love them and sometimes you wish they weren’t there. If you work in remote sensing with satellite images you probably hate them.

How many pixels are in a Sentinel 2 Scene?

Over the last couple of years, Hollstein et al. curated a data set consisting of around 6.4 million hand labeled pixels from 108 Sentinel-2 scenes sampled roughly evenly from around the globe and throughout the year to ensure full climatic coverage.