On Monday Nov 14 New Zealand was hit by an earthquake of magnitude 7.8. The epicenter was located near Kaikoura on the east coast of the South Island.
Yesterday, the NZ Herald published aerial photographs showing tectonic uplift of the seabed of between 2 and 2.5 metres north of Kaikoura . These photos were taken by @TonkinTaylor who posted them on Twitter.
A Pléiades stereo pair has been acquired on 2016-Oct-01 just a few days after the second glacier collapse in the Aru mountains. The panchromatic band has 0.5 m resolution, which allowed us to generate a post-event digital elevation model of the area. From this digital elevation model and the Pléiades 2 m multispectral imagery, Etienne Berthier generated these stunning 3D views of the aftermath...
Preliminary estimates of the volume detached from the glaciers are 66 Mm3 (first, north one) 83 Mm3 (second, southern one).
"The most usual weather in these latitudes is a fresh wind between north west and south west with a cloudy overcast sky" - Phillip Parker King, Sailing Directions for the Coasts of Eastern and Western Patagonia (1832).
Patagonia is a beautiful place to visit but campers know that the weather is extremely variable and the sky is often cloudy. This can be a problem for glaciologists, too, since they rely on optical satellite imagery to study glacier area changes over the last decades (mainly Landsat). Clear-sky optical images can also be used to determine glacier velocity, albedo, front variations, etc.
The giant ice avalanche that occurred in Tibet on 17 July 2016 and killed 9 people  urged scientists to scrutinize every available data to understand what caused such a glacier collapse. In doing so, they witnessed in near real time the ongoing collapse of a second glacier.
We are preparing the distribution of maps of the snow cover extent made from the Sentinel-2 data for Theia. If the method used to detect the snow is based on well-proven concepts, spatial and temporal resolution of the snow maps will however quite unprecedented. Until now, maps of the snow cover extent were usually produced from MODIS observations at 500 m resolution, which is adapted to hydro-climatic studies to rather regional scales. Landsat data were actually little exploited by snow scientists because of their low repeatability. The deployment of Sentinel-2 mission (global coverage at 20 m resolution every 5 days) opens new perspectives for monitoring snow cover.
Dans le cadre du pôle thématique Theia nous préparons la distribution de cartes d'enneigement établies à partir des images Sentinel-2. Si la méthode utilisée pour la détection du manteau neigeux se base sur des concepts bien éprouvés, la résolution spatio-temporelle des cartes d'enneigement sera en revanche tout à fait inédite. Jusqu'ici les cartes d'enneigement était généralement produites à partir des observations MODIS à 500 m de résolution ce qui permet de faire des études hydro-climatiques à des échelles plutôt régionales. Les données Landsat étaient finalement assez peu exploitées par les nivologues en raison de leur faible répétitivité. Le déploiement de la mission Sentinel-2 (couverture globale à 20 m de résolution tous les 5 jours) ouvre de nouvelles perspectives pour le suivi de l'enneigement.
Nous avons deux gagnants ! We have two winners to the Sentinel-2 contest - Grand jeu-concours: Rutger & François! Bravo!
Play to win the prize: ONE YEAR OF FREE SUBSCRIPTION to the blog "Séries Temporelles"!
Jouez pour gagner : UN AN D'ABONNEMENT GRATUIT au blog "Séries Temporelles" !
The Daldykan River is a tributary of the Ambarnaya River, which feeds the Lake Pyasino in Siberia (738 km²). According to Wikipedia in English Lake Pyasino "is almost completely devoid of ﬁsh". However, Wikipedia in French states that "Il est très poissonneux" (full of fish).
Wildfires were raging in California this summer. Let's see if we can spot some of them in Sentinel-2A images with the new Sentinel-Playground by Sinergise.
The combination of the SWIR and NIR bands of Sentinel-2 or Landsat enables to produce accurate maps of burnt areas. The SWIR band is sensitive to the water content in the soil and vegetation, while the NIR band is sensitive to the vegetation health (photosynthetic activity).
In addition, the radiance measured by a spaceborne sensor in the SWIR wavelengths increases if the surface is very hot (as taught us Prof. Planck in Hawaïï).
As a result, a simple color composite of bands SWIR/NIR/Red gives a stunning view of burnt areas and can highlight ongoing fire areas if the smoke is not too opaque.
In Coalinga, the Mineral Fire burnt nearly 3000 ha close to the city of Coalinga.
Mineral wildfire near Coalinga, Californa USA. Time series of Sentinel-2A images (RGB color composite of bands SWIR/NIR/Red = 12/8A/4)