# EOLIS Today

Monthly images and analysis of the volume change of the world’s land ice

## WHAT'S HAPPENING TO ICELAND'S GLACIERS?

Over the past five years, Iceland’s glaciers have been shrinking at an alarming rate due to rising temperatures driven by climate change. Warmer summers and milder winters have accelerated the melting of the glaciers, leading to significant ice loss.

This ice loss contributes to rising sea levels and disrupts ecosystems, as well as impacting local industries like hydropower and tourism. If current trends continue, some of Iceland’s smaller glaciers may disappear within the next century.

## 5-YEAR RATE OF CHANGE ANOMALIES

## WHOLE MISSION RATE OF CHANGE

## HYPSOMETRY

## CUMULATIVE ELEVATION CHANGE

## SEASONAL CYCLES

## ADDITIONAL INFORMATION ABOUT THE DATA AND DISPLAY

This information presented on this web page is derived from the CryoTEMPO EOLIS Gridded Product. The information within this product is regularly loaded into Specklia, and then from there, processed automatically to produce the plots and values shown above. This section provides a short summary of the processing completed for each plot or figure.

#### Mass change measurement

The mass change measurement at the top of the page is computed via the following steps:

- A reference DEM is calculated by averaging the first six months of CryoTEMPO EOLIS Gridded Product elevation data, and subtracted from the most recent month’s data to produce a DEM difference measure. As not every month of data will cover every posting, this DEM difference measure will have gaps.
- A dh/dt is calculated by applying a linear regression for each individual CryoTEMPO EOLIS Gridded Product pixel over the entire span of the mission, and used to fill gaps in the DEM difference.
- Any DEM difference values more than 3 standard deviations from the mean are classes as outliers and replaced via hypsometric averaging of the dh/dt.
- For each Randolph Glacier Inventory v7 glacier, all of the DEM difference pixels that overlap it are averaged, and this value is used together with the area of the glacier to calculate a volume change for the glacier.
- Volume changes for all glaciers that are covered by the CryoTEMPO EOLIS Gridded Product are summed and converted to ice mass loss via a fixed ice density.
- The final mass loss figure is produced by combining this measure with the output of GLaMBIE.

#### 5-year rate of change anomalies

This plot shows a comparison between two dh/dt measurements for the region. To produce it, a linear regression is performed for each individual CryoTEMPO EOLIS Gridded Product pixel over the last five years, and a separate linear regression for the five years before that. These dh/dts are subtracted from each other, illustrating accelerations in elevation loss over that timescale. The data produced are then treated as a raster image, and reprojected to the display coordinate reference system using nearest neighbour interpolation. Once in the display coordinate reference system, any pixels more than five standard deviations away from the mean are removed, and the result is smoothed through convolution with a gaussian kernel of width 5 pixels. The raster is plotted overlaid on a greyscale version of the Esri WorldShadedRelief map, where water is assigned a specific grey.

#### Whole mission rate of change

This plot is produced exactly the same way as the 5-year rate of change anomalies plot, except a single dh/dt is calculated over the timescale of the entire mission.

#### Hypsometry

A reference DEM is calculated in the same manner as for the mass change measurement, and the result binned in elevation, producing the teal histogram. dh/dts calculated as per the previous two plots are then binned identically, and plotted over the top as lines.

#### Cumulative elevation change

Here, a reference DEM is calculated in the same manner as for the mass change measurement, and the result is subtracted from each month’s data. The mean over each month is then taken, and the result finally passed through an exponentially weighted mean over time with a 30 day half-life. Note that “coverage” here is defined as the fraction of the coverage of the glaciated area as defined by the Randolph Glacier Inventory v7.

#### Seasonal cycles

This graph is produced similarly to the cumulative elevation change graph, except the simple difference between the cumulative elevation change of successive adjacent months is shown. Different statistics are shown for the user’s convenience. Coverage on this plot is defined identically to coverage on the cumulative elevation change plot.

#### For further information

Many features of EOLIS Today are available via Earthwave API for rapid integration into your own projects and websites. Further detail is available on request; please contact us with any further questions you may have.