Lecture 3

Question 1

what is the .408 for

Answer 1

to convert from the latent heat units to mm d-1

Question 2

what is Rs

Answer 2

solar radiation

Question 3

what is Rso

Answer 3

clear sky radiation

Question 4

what is Ra

Answer 4

extraterrestrial radiation

Question 5

what is G and what does it mean if neg/pos

Answer 5

G is the ground flux density , the thermal energy utilised to heat the soil

posistive means warming negative means cooling

Question 6

what is delta

Answer 6

slope of the saturation vapourisation pressure-temperature curve

Question 7

what is Cn

Answer 7

constant to do with aerodynamiuc roughness

Question 8

what is Cd

Answer 8

constant to do with aerodynamic roughness and bulk surface resistance

Question 9

what are cn and Cd suprisingly sensitive to

Answer 9

day and night

Question 10

what is the tall reference crop definition

Answer 10

a crop 0.5 m tall, surface resistance of 50 s m-1 and an abedo of 0.23

Question 11

what is gamma

Answer 11

psychometric constant

Question 12

what is a basic conclusion from tonnys research

Answer 12

up to 50% saving in summer

10-20% annual saving

Question 13

when not use G when use G

Answer 13

not use for day to day, or annual, but use for hourly or monthly