Merge pull request orcestra-campaign#73 from orcestra-campaign/Lucali…

…no-patch-1

Correct approximate circle radii in README.md

README.md

@@ -55,7 +55,7 @@ segments:
 Kinds may or may not apply/be adopted for all platforms. For version 1 of the segmentation of HALO flights, one or more of the following kinds are assigned to each segment:
 
 ### circle:
-- can be identified by a constant change of aircraft heading, a duration of about 60 min , as well as a roughly constant roll angle of 1.5-3 degrees (positive or negative, depending on turning clockwise or counter-clockwise) for the standard circle of about 200km diameter. Duration and roll angle change with the chosen circle radius. The smaller ATR circle has about 140km diameter and a larger roll angle of 3-5 degree depending on and varying with the wind speed and direction at the respective altitude.
+- can be identified by a constant change of aircraft heading, a duration of about 60 min, as well as a roughly constant roll angle of 1.5-3 degrees (positive or negative, depending on turning clockwise or counter-clockwise) for the standard circle with a radius of about 133km. Duration and roll angle change with the chosen circle radius. The smaller ATR circle has a radius of approximately 70km and a larger roll angle of 3-5 degree depending on and varying with the wind speed and direction at the respective altitude.
 - in most cases associated with the launch of dropsondes, typically 12 per circle at every 30° heading. In cases where the first/last dropsonde of the circle was launched before/after the roll angle and change in heading match the circle characteristics described above, the start/end time of the circle segment is taken to be the `launch_time` of the respective dropsonde minus/plus 1 sec. 
 - Circle dropsondes were sometimes droped before/after the roll angle reached its circle value in which case the launch time of the sonde  marks the beginning/end of the circle period (minus/plus a few seconds, so that the sonde is included in the circle segment). 
 - Some circles were highly irregular due to detours around convective towers. In these cases, an irregularity note need to be added.