Monitoring Agricultural Drought in Russia - Monitoring and Predicting Agricultural Drought: A Global Study - page 201

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where W means water storage in the corresponding soil layer available to
plants, 0-100 (i

1) is the index showing thickness of relevant soil layer,
and i is the number of the dekad.
The above indices are widely used in all CIS countries. In Ukraine
the drought conditions are also estimated from the index developed by
Dmitrienko (1978, 1992):
ξ = η( W )β + η( T )η( R ) 1

−

− γ( d ) ( 1

− β) [15.4]

where ξ is the complex dryness index in terms of relative crop yield; η(W)
is the field crop productivity coefficient derived from soil water reserves,
W ; β is the weight coefficient; η(T ), η(R) are the temperature, T , and
precipitation, R , coefficients of field crop productivity; and γ

is the index

of crop depression from the hot wind impact, d .

[201

D rought Index

Line
——
-0.3
——
Long
PgEn

Specialists and scientists working in the field of agrometeorology accept
the drought index developed by Ped (1975):

T
σ T −

R
σ R −

E
σ E

S i (τ ) = [15.5]

where S i is the drought index which is the sum of anomalous weather
conditions, i is the site; τ is the time; T is the mean air temperature
deviation from the normal ( T N ) during a period T ; R is the deviation
in precipitation from the normal ( R N ) during a period ( R ); E is the
deviation of moisture reserves in a 1-m soil layer ( E ) from the normal ( E N );
and σ T , σ R , and σ E are the root-mean-square deviation in temperature,
precipitation, and moisture reserve, respectively.
Zoidze and Khomyakova (2000) analyzed the above indices and also
the following indices to describe drought conditions: (1) maximum air
temperatures above 30, 35, 40, and 45°C in dekads, (2) rainless periods of
different durations, (3) relative air humidity of 30% or less, (4) productive
moisture reserves in the 0-20 and 0-100 cm soil layers during winter, early
and later spring cereals at the beginning of sowing and mass development
phase as well as for individual vegetation months of these crops, (5) water
vapor saturation deficit in air at 1500 h at various wind velocities, and (6)
crop yield deviations depending on arid conditions.
Until 1917, the Science Committee of Meteorological Agency of the
Central Land Organization and Farming Administration monitored
droughts in Russia and published map showing probability of dry dekads
in the European Russia (Brounov, 1913); a dekad during which the pre-
cipitation did not exceed 5 mm was considered a dry dekad. In Soviet and
post-Soviet periods, the Hydrometeorological Service monitored drought.
This agency collects information about droughts in the Russian Federa-
tion regions and submits it to the Ministry of Agriculture and other fed-
eral authorities. For the past 20-30 years, the agency has published and
updated various agroclimatic reference manuals. For example, two guide

[201