Derived Fields - Scientific Visualization: Uncertainty, Multifield, Biomedical, and Scalable Visualization - page 140

(a)

(b) (c)

(d) (e)

F computed for wind velocities over the years 1960-
2009, where the comparison is over a set of six hundred 3D vector fields. a Map of world showing
wind patterns ( source Wikipedia). b Distribution of

Fig. 14.7 Multifield comparison measure η

F over surface corresponding to pressure
elevation 925 hPa. The dark red regions correspond to the wind patterns. c Distribution of

η

F over
surface corresponding to pressure elevation 300 hPa. The temperate regions exhibit higher values.
d Storm track for the years 1985-2005 ( source Wikipedia). e Distribution of

η

F

η after removing

27 ◦ C). Red regions correspond to the storm tracks. The
world map is overlaid for clarity. Image courtesy of Nagaraj et al. [ 14 ]

regions with low mean temperature ( <

correspond to the prevailing winds, particularly the westerlies found in the regions
surrounding Antarctica, the region of hurricanes in Atlantic, the cyclone prone region
between Madagascar and Australia, and the trade winds across the Atlantic sea
traveling towards the Caribbean sea. The distribution of the comparisonmeasure over
the isobar for pressure level 300 hPa, which corresponds to approximately 30,000 feet
above sea level, is shown in Fig. 14.7 c. The comparison measure assumes high values
over the temperate regions corresponding to thewesterly jet. This is a semi-permanent
feature of the mid-latitudes. Many regions in the tropics undergo a seasonal reversal
of wind (called the monsoons). Lower values of the comparison measure over the
tropics indicates unsteadiness and corresponds to a seasonal reversal in wind pattern
over this part of the world.