I work primarily with observations (i.e. data). I am interested in the large-scale monitoring of the Earth’s surface and climate. My past and current work include the mapping and change detection of Earth’s topography, bathymetry and gravity field, as observed by radars, lidars, imagery, sonars and gravimeters, among others. I develop algorithms for remote-sensing applications and use high-performance computing (clusters) to process large-scale satellite measurements. I am a strong advocate of open source and open data!

## Time-varying melt rates from Antarctica

A Greatly Improved 25-year Record of Ice Shelf Elevation at High Temporal and Spatial Resolution

Constructing ice-shelf melt-rate time series (meltwater production) at unprecedented spatiotemporal resolution. Satellites: ERS-1 + ERS-2 + Envisat + CryoSat-2 + ICESat + ICESat-2. Time span: 1992-present (27+ years). Temporal resolution: 3 months. Spatial resolution: 3-5 km. Grid posting: 1 km. Authors: Paolo, Nilsson, Gardner (JPL).

## Ice-sheet mass change

Integration of nearly 30 years of disparate satellite altimetry observations of the Antarctic ice sheet, 1985-present

State-of-the-art surface elevation-change time series for the majority of the Antarctic Ice Sheet since 1985 to present, estimated from six satellite missions (Geosat, ERS-1, ERS-2, Envisat, ICESat and CryoSat-2). This allows us to study decadal and multi-decadal trends as well as short-term variability at fine spatial resolution; providing an invaluable dataset for advancing ice-sheet data assimilation efforts into climate models and for disentangling the causal mechanisms responsible for ice-sheet mass change.

## MEaSUREs ITS_LIVE

NASA MEaSUREs Inter-mission Time Series of Land Ice Velocity and Elevation (ITS_LIVE)

## Multi-satellite Data Fusion

Constructing long-term continous time series of ice-shelf height change from multiple satellite altimeters.

Figure: Representation of our multi-referenced time series approach. (Left) individual time series of cumulative change. (Right) diagram representing the matrix formed with the time series on the left (one time series per row). From top to bottom is depicted the process of forming single-grid-cell frequency-average time series.

Check out our paper in Remote Sensing of Environment

## Geophysical Data Analysis

Large-scale processing, statistical modeling and time series analysis applied to Earth observations.

Figure: Modes of oscillation in the ice-shelf height time series. (left) The empirical orthogonal functions paired as EOFs 1–2, 3–4 (interannual components) and 5–6 (annual component). Note the phase quadrature (∼π/2 shift) between pairs. (right) The reconstruction of each pair of modes in the time domain. This is equivalent to filtering the original time series (in gray) with respect to particular frequencies.

Check out my PhD Dissertation

## Ice-shelf thickness change from Satellite Altimetry

Multi-mission satellite altimetry to investigate long-term trends and variability in Antarctic ice-shelf thickness.

Figure: Eighteen years of changes in the Antarctic ice shelves. Color map is rate of thickness change, circles are percentage thickness gained or lost, time series are mean ice-volume change over 18 years. There is considerable variability in the height-change signal, and trends on short time intervals are not representative of the underlying decadal trends.

Check out our paper in Science

## Marine Gravity Field from Satellite Altimetry

Satellite altimeter-derived sea surface gradient and shipborne gravity for an integrated marine gravity field.

Figure: Integrated gravity models constructed using sea surface gradients (slopes), derived from satellite altimetry (Geosat and ERS-1), and marine gravity data (ships) along the Brazilian coast: (left) free-air gravity anomaly and (right) geoid height. Unlike spectral methods (deterministic approach), the least squares collocation (stochastic approach) presented a low content of high-frequency noise in the predicted gravity anomalies.

Check out our paper in Journal of Geodynamics