“Seeing” large data sets Reanalyses   Systems   generate   huge   amounts   of   data   that   cannot   be   absorbed   by   the   human   mind without   further   refinement   and   interpretation.      One   tool   that   helps   to   make   the   data   more   accessible, understandable    and    usable    is    data    “visualisation”.        Users    generate    a    query    describing    the    data elements   they   want   displayed,   the   time   period   they   want   covered   and   the   visual   elements   they   want used   (eg.   colour,   image   size,   etc.).      A   graphic   is   then   presented,   giving   the   user      a   clear   visual representation   of   otherwise   complex   data.      The   graphic   can   be   a   still   image   or   an   animation,   for instance:

Tropopause 1000mb Zonal Wind (m/s) composite mean From 20CR Reanalysis system

Air temperature (degK) composite winds October 1899 to Oct 1900

The Weather of October 1918 (20CR system)

 NASA has plotted GEOS5 aerosols:

A time series visualisation of weather observation data contained in the International Surface Pressure Databank

Movements of the 250 ships whose logbooks were digitised by the oldWeather project (1914-1923)

A visualisation of the impact that observations contributed by ACRE partners had on the 20CR reconstruction of the weather of 1916.  It shows: • earlier contributions made by ACRE partners and those more recently made. • The “fog of ignorance” showing global regions where the reconstructions are still very uncertain because there are too few observations. • The “glow of discovery” showing regions where the new observations have produced a large improvement in the confidence of the reconstructions.

LINKS 20CR visualisations can be generated online Further visualisations of ACRE assisted reanalyses

NCAR has plotted an East Asia coastal cyclone