Campbell Scientific PWS100 Present Weather Sensor - Manual (Page 114)

Appendix A. PWS100 Output Codes
However it is also noted that non-mixed reports such as rain or snow may also
contain a proportion of other types of particle such as drizzle which is not
included in any intensity range modification for non-mixed reports. Without
modifying on the proportion of identified particle types this is an inaccuracy
that will be inherent in some data though statistically should not be extremely
significant and certainly less so than choosing the largest range of the mixed
types observed. The values given in Table A-1 are from mixed events with
fixed range values (as calculated in Tables A-3 to A-8) rounded to 1 d.p.
Table A-3 gives mixed intensity ranges for rain and drizzle (liquid precipitation
WMO 43, 44 and freezing precipitation WMO 47, 48), Table A-4 gives mixed
intensity ranges for rain and snow (WMO 68), Table A-5 gives mixed intensity
ranges for drizzle and snow (WMO 68), Table A-6 gives mixed intensity
ranges for rain, drizzle and snow (WMO 68), Table A-7 gives mixed intensity
ranges for rain, drizzle, ice pellets, hail and snow (precipitation WMO 41, 42),
Table A-8 gives mixed intensity ranges for ice pellets, hail and snow (solid
precipitation WMO 45, 46).
TABLE A-3. Intensity bounds for rain and drizzle.
Rain Drizzle Rain and Drizzle (same for freezing)
Light
i<2.5 i<0.1 i<1/2 Ч2.5+1/2Ч0.1
i<1.3 mmh -1
Moderate
2.5≤i<10.0 0.1≤i<0.5
1/2 Ч2.5+1/2Ч0.1
≤ i<1/2 Ч10+1/2Ч0.5
1.3 mmh -1 ≤ i<5.25 mmh -1
Heavy
i≥10.0 i≥0.5 i≥ 1/2 Ч10 + 1/2 Ч0.5
i≥5.25 mmh -1
TABLE A-4. Intensity bounds for rain and snow.
Rain Snow Rain and Snow
Light
i<2.5 i<1.0 i<1/2 Ч2.5+1/2Ч1.0
i<1.75 mmh -1
Moderate
2.5≤i<10.0 1.0≤i<5.0 1/2 Ч2.5+1/2Ч1.0
≤ i<1/2 Ч10+1/2Ч5.0
1.75 mmh -1 ≤ i<7.5 mmh -1
Heavy
i≥10.0 i≥5.0 i≥ 1/2 Ч10+1/2Ч5.0
i≥7.5 mmh -1
TABLE A-5. Intensity bounds for drizzle and snow.
Drizzle Snow Drizzle and Snow
Light
i<0.1 i<1.0 i<1/2 Ч0.1+1/2Ч1.0
i<0.55 mmh -1
Moderate
0.1≤i<0.5 1.0≤i<5.0 1/2 Ч0.1+1/2Ч1.0 ≤ i<1/2 Ч0.5+1/2Ч5.0
0.55 mmh -1 ≤ i<2.75 mmh -1
Heavy
i≥0.5 i≥5.0 i≥ 1/2 Ч0.5+1/2Ч5.0
i≥2.75 mmh -1
A-8