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Đơn vị Hành chính, đất đai và khí hậu - Administrative Unit, Land and Climate 10
EXPLANATION OF TERMINOLOGY, CONTENT
AND METHODOLOGY OF SOME STATISTICAL INDICATORS
ON LAND, CLIMATE
LAND
Agriculture production land
refers to the land used in agricultural production; including:
annual crop land and perennial crop land.
Forestry land
refers to the land used in forestal production or experiment, including:
productive forest, protective forest and specially used forest.
Specially used land
is land being used for other purposes, not for agriculture, forestry and
living. It includes land used by offices and non-profit agencies; security and defence land; land
for non-agricultural production and business and public land.
Homestead land
is land used for house and other works construction serving living
activities of urban and rural inhabitants.
CLIMATE
Number of sunshine hours in months
is the sum of sunshine hours of days in the month.
Number of sunshine hours or the number of hours with direct solar radiation is equaled or
exceeded 0.1 kw/m
2
(≥ 0.2 calo/cm
2
min.). Sunshine duration is measured by heliograph. It is
identified by the burn in the paper diagram engraved time due to convergence of sunrays through
the glass sphere.
Total sunshine hours in the year
is the total of sunshine hours of days in the year.
Rainfall in months
is the total rainfall of all days in month.
Rainfall
is the thickness
(measured in ml) of water created by rainfall on the flat surface at one location, measured by
rain-gauge/ pluviometer.
Total rainfall in year
is the total rainfall of days in the year.
Average humidity in months
is the average of relative humidity of days in the month.
Average humidity in year
is the average of relative humidity of days in the year.
•
Relative humidity
is the ratio of the vapor in the air and saturate vapor (maximum) at the
same temperature. It is indicated under percent form (%). Humidity is measured by hygro meter
and hygro graph.
•
Daily average relative humidity
is the average results of 4 main observations at different
time in a day: 1 a.m, 7 a.m, 13 p.m, 19 p.m or from the results of 24 observations at from 1 a.m, 2
a.m, 3 a.m,... to 24 p.m of the hygro graph.
Average air temperature in months
is the average of average air temperature of days in
the month.
Average air temperature in year
is the average of average air temperature of days in the
year.
•
Air temperature
is measured by normal thermometer, mercury thermometer, alcohol
liquid thermometer and thermo graph (induction part is made from bi-metal) exposed to the air in
a meteor bust at 2m from the ground, sheltered from direct solar radiation.
•
Daily average air temperature
is the average of the results of 4 main observations in a day
at 1 a.m, 7 a.m, 13 p.m, 19 p.m or from the results of 24 observations at from 1 a.m, 2 a.m, 3
a.m,... to 24 p.m of the thermometer.