Vaisala RS41, Руководство пользователя

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Chapter 3 _________________________________________________________ Ozone Calculation
VAISALA_______________________________________________________________________ 85
CHAPTER 3
OZONE CALCULATION
This chapter describes ozone calculation in detail.
The ozone data is combined with meteorological radiosonde data:
pressure (P), temperature (T) and relative humidity (U) in the ground
equipment. The measuring sample interval (measures each sensor once)
of Radiosonde RS41-SG is 1 second. OIF411 is scanned in phase with
the radiosonde PTU measuring sequence. Therefore, all the measured
data is synchronized.
Averaging and Eliminating Irrelevant Measuring
Results
Noise filtering helps to eliminate erroneous data. Errors may originate
from various different phenomena, for example, from electrical spikes.
The filtering is made by calculating the median of a given number of
consecutive samples. The median is the middlemost sample in the order
of magnitude. This algorithm cuts all remarkably higher and lower
measurement results compared with other measurement results near the
measurement (in a given time window). The filtering window (the
number of consecutive samples, where the median is made) is given to
the ground equipment during ozone sounding preparation.
The median calculation algorithm is well-defined for odd values only:
number of filtering window length (1, 3, 5, 7, ...) (number of
measurement samples in the window). Therefore, the filtering window
is defined in the ground equipment as the window radius; from the