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Wokingham, England, United Kingdom of Great Britain and Northern Ireland

Latitude: 51° 25' 4'' N

Longitude: 0° 51' 49'' W

20 February 2016 1505 (Local Time)

Image P/S code: P.11.2.1

Image I.D.: 4759

Rain and drizzle
This photograph gives an illustration of the relative size of drops of rain and of drizzle. Each graduation on the ruler is 1 mm.

The ruler was exposed to moderate precipitation in the form of rain and drizzle mixed (present weather code 59) for about 1 minute during a period in which the rate of accumulation was about 0.6 mm/hr.

A wave on a cold front had recently passed east over the location in southern England, UK and had reintroduced the location to a warm-sector airflow. A 1200 UTC upper-air sounding from Camborne, England, UK (approximately 335 km to the west-south-west of the observing location and within the warm-sector airflow) indicates extensive low-level cloud of Stratus and Stratocumulus to a top of around 830 hPa, with further layers of medium-level cloud above. It is likely that the relatively few, larger rain drops originated in the medium-level cloud, while the more numerous drizzle drops would have fallen from the low Stratus layer.

Drizzle drops are usually less than 0.5 mm in diameter, while rain drops are larger than this and vary according to the intensity and nature of the precipitation. The relative sizes are illustrated well in this photograph, although it must be noted that due to the squashing of the larger raindrops on the ruler (caused by gravity and/or surface tension), these drops appear slightly larger than their true diameter when in freefall through the air. Nevertheless, the image illustrates how rain and drizzle drops would appear, for example, once they have fallen onto the lenses of an observer's spectacles – a useful aid to help determine whether precipitation is drizzle, rain, or a mixture of the two.
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© George Anderson
Wokingham, England, United Kingdom of Great Britain and Northern Ireland
Latitude: 51° 25' 4'' N
Longitude: 0° 51' 49'' W
20 February 2016 1505 (Local Time)

Image P/S code: P.11.2.1
Image I.D.: 4759
A wave on the cold front had recently moved east through the observing location and had reintroduced the location to a warm-sector airflow.
© Crown Copyright
Camborne, England, UK is approximately 335 km to the west-south-west of Wokingham. At the time of the upper-air ascent, Camborne was within the warm-sector airflow.
© University of Wyoming

Rain and drizzle