Vegetation height is one of the leading dimensions of ecological variations among tree species and is central to ecosystem functioning [1]. Since its launch in 2003, GLAS (Geoscience Laser Altimeter System) on board ICESat (Ice, Cloud,and land Elevation Satellite) has produced unprecedented dataset at the global scale [2]. However, the challenge to retrieve canopy height from large-footprint sa...

Introduction: The topography of Mars is a key parameter for the understanding of the geological evolution of the planet [1]. Topographic data for most applications are represented as Digital Elevation Models (DEMs). DEMs are characterized by their spatial resolution (distance between neighbor points on the topographic grid) and the accuracy of elevations. The resolution and accuracy required de...

The Mercury Laser Altimeter (MLA) measured surface reflectance, rs, at 1064 nm. On Mercury, most water-ice deposits have anomalously low rs values indicative of an insulating layer beneath which ice is buried. Previous detections of surface water ice (without an insulating layer) were limited to seven possible craters. Here we map rs in three additional permanently shadowed craters that host ra...

The requirement to operate aircrafts in GPS denied environments can be met by use of visual odometry. We study the case that the height of the aircraft above the ground can be measured by an altimeter. Even with a high quality INS that the orientation drift is neglectable, random noise exists in the INS orientation. The noise can lead to the error of position estimate, which accumulates over ti...

We present maps of the topographic roughness of the northern circumpolar area of 30 Mercury at kilometer scales. The maps are derived from range profiles obtained by the 31 Mercury Laser Altimeter (MLA) instrument onboard the MErcury Surface, Space 32 ENvironment, Geochemistry, and Ranging (MESSENGER) mission. As measures of 33 roughness, we used the interquartile range of profile curvature at ...

[1] We perform a series of Observing System Experiments (OSEs), where components of the Global Ocean Observing System (GOOS) are systematically withheld from a data assimilating ocean reanalysis. We assess the relative importance of Argo temperature (T) and salinity (S) profiles, sea-surface temperature (SST) and altimetric sea-level anomalies (SLA) for constraining upper-ocean T and S properti...

Changes in the sea surface heights (SSH) and geostrophic transports in the NE Pacific are examined during the 1997–1998 El Niño using altimeter data, sea level pressure (SLP) fields, proxy winds and satellite sea surface temperature (SST). Most of the signal occurs along the boundaries of the basin from Panama to the Alaska Peninsula. Changes in the SSH and alongshore transports along the bound...

Algerian eddies are the strongest and largest propagating mesoscale structures in the Western Mediterranean Sea. They have a large influence on the mean circulation, water masses and biological processes. Over 20 years of satellite altimeter data have been analyzed to characterize the propagation of these eddies using automatic detection methods and cross-correlation analysis. We found that, on...

We analyse the North Atlantic circulation by combining data from ARGO profiling buoys and satellite altimetry measurements into an inverse finite-element ocean circulation model. The model solution is consistent with ocean dynamics and approximate conservation of temperature and salinity. The ocean circulation is analysed separately for the years 2005 and 2006. Temperature and salinity fields f...

The authors report the first results in studying the polarization anisotropy of the microwave backscatter from nadir observations provided by Jason-1 altimeter in both Kuand C-band. A small but clear wind direction signal for wind speeds above 6 m/s is revealed. These azimuthal variations of radar cross-section increase with increasing wind speed up to 14 m/s. The signatures then level off at h...