Volcanic Databases of the Transient Aerosol Record (TAR) Experiment

TAR defines a set of experiments for global climate models with the aim to explore the role of small- to moderate-magnitude volcanic eruptions, anthropogenic sulphur emissions and atmospheric transport processes over the period 1998-2012 in view of their effects on global climate warming.

TAR is one of four sets of experiments defined within the comprehensive climate model research initiative ISA-MIP (Interactive Stratospheric Aerosol Model Intercomparison Project). It was initiated in 2013 by the Stratospheric Sulfur and its Role in Climate (SSiRC) research cluster as part of the WCRP (World Climate Research Programme) activity SPARC (Stratosphere-Troposphere Processes And their Role in Climate).

TAR provides six volcanic databases for the application in aerosol- and chemistry-coupled global climate models.

The databases are explained in an Open Access paper in the Journal "Geoscientific Model Development" (Copernicus Publications), providing an overview of all ISA-MIP specifications and describes the initiative's scientific background:
Timmreck, C., Mann, G.W., Aquila, V., Hommel, R., Lee, L.A. , Schmidt, A., Brühl, C., Carn, S., Chin, M., Dhomse, S.S., Diehl, T., English, J. M. , Mills, M.J., Neely, R., Sheng, J.-X., Toohey, M., and Weisenstein,D.: The Interactive Stratospheric Aerosol Model Intercomparison Project (ISA-MIP): Motivation and experimental design, Geosci. Model. Dev. Disc., doi: 10.5194/gmd-2017-308, 2017. [Online Article] [PDF]

TAR is coordinated by Dr Valentina Aquila (American University, NASA Goddard) and Dr René Hommel (Hommel & Graf Environmental).

Interactive Visualisation of Volcanic Datasets 1-3 for TAR Tier 1 Experiments

Hommel & Graf Environmental compiled an interactive visualisation to illustrate the content of the TAR Tier 1 experiment datasets. It allows a simple evaluation of the different characteristics of the three datasets.

The visualisation shows two graphs: a map on top, and a time-series below. The quantity visualised is the emitted mass of Sulphur Dioxide (SO2) in units of kilotons [kt] of each volcano considered in the datasets.

The map shows the global distribution of emitted SO2 of each volcano. The time-series graph depicts the corresponding temporal evolution of all eruptions in the chosen time frame.

It has to be noted that map data are cumulative masses of SO2 injected by each volcano in the selected period. The time-series, in contrast, depicts the emitted SO2 mass for each volcanic eruption of the dataset in a non-accumulated manner. Therefore, the SO2 mass is higher on the map than in the time-series, when a specific volcano erupted several times a year. Those eruptions are well expressed in the time-series, showing a "tail" of extended SO2 injections over time. Frequently, volcanic eruptions last longer than a single day. Good examples are the eruptions of the volcanos Nabro (Ethiopia) and Nyamuragira (DR Congo) in June and November-December 2011, respectively, in the datasets 2 and 3.

By illustrative purposes, the scale of SO2 amounts (circles) is six times higher in the map than in the time-series. Using the same scale result either in too small circles drawn on the map or overproportioned circles in the time-series. We additionally colour coded each volcano to allow visual tracing of their location (in the map) and time of eruption (in the time-series).

Dataset 1 apparently shows lower SO2 amounts compared to the other datasets. That is because Dataset 1 is compiled only for SO2 amounts that are directly injected into the stratosphere.


The visualisation is build using the D3.js JavaScript library for visualising data with HTML, SVG, and CSS. The chart is not (yet) responsive and requires a minimum horizontal viewport of 960 pixels (browser window's inner width) to apply all functionality.

Please address your questions, comments, and suggestions directly to contact@env.earth.

Further Information about TAR and associated research inititives can be found here: