Studies on the micrometeorology in the sloping orchards. 2

Abstract

1. From July, 1947 to August, 1950, the author observed the air temperature near the ground and the under-ground on the field, on the persimmon orchard of the southwestern slope and on the orange orchard of the northeastern slope, once or twice a month on a fine day, at every two hours for 24 hours running, and examined the daily variation of the temperature on each of the slope.
The state of its distribution almost agrees with that of the amount of insolation, and the differ-ence of temperature on the upper and lower parts of the slope being so small, the average differ-ence proved to be about 1°C daily.
2. The daily average temperature is, at each slope, the highest in August both on and under the ground. On the ground and up to 10cm under it, it is the lowest in January, and near 50cm under the ground, it is the lowest in February.
3. The diurnal range of the temperature is, at every slope, the largest' on the ground sur-face, and the partial difference is also large. It decreases as it goes up or down from the ground, and especially it decreases suddenly as the sta-tion becomes deeper, and becomes zero about 50cm under the ground, which shows the depth of daily permeation of heat.
Every month the diurnal range of temperature is large on the field in the southwestern slope, and is the smallest on the orange orchard in the northeastern slope, and it is about medial of the two, on the persimmon orchard in the southwes-tern slope, but in the cold season, every diurnal range is small.
The diurnal range was large about April and August and the smallest in February.
4. The difference of temperature between each observation point is the largest on the ground sur-face, and becomes gradually smaller as it goes up or down, but up to 10cm from the surface or under the ground it is large. This is especially large in April and August when the diurnal range is large, and is small in cold seasons.
5. I examined the vertical distribution of the air temperature near and under the ground of each slope.
The vertical distribution of the daily average temperature showed simply, at every observation point, an incoming radiation type in spring and summer.
An outgoing radiation type was shown under the ground in autumn and winter, but towards December and January when the amount of the incoming radiation is small, the air temperature near the ground also showed the outgoing radia-tion type, and the northeastern slope already showed it in September earlier than the other slopes.
6. In warm seasons -in spring and summer, the vertical distribution of the average temperature in the daytime showed the incoming radiation type almost without exception, but in the persimmon orchard, part of the outgoing radiation type or a type approximate to it was shown.
The vertical distribution of average temperature during the night showed the outgoing radiation type at every part of the underground, and the air temperature near the ground showed simply the outgoing radiation type in March and April, but in May instead of showing simply the outgo-ing radiation type as Dr. R. GEIGER brought for-ward a minimum air temperature appeared about 10cm about the surface of the ground.
After June when it is warm, the outgoing radiation type hardly came to appear in the air temperature near the ground.
In autumn and winter, every daytime showed the incoming radiation type, but on the north-eastern slope, the time to show the incoming radiation type became shorter and shorter.
During the night, except in September, every observation point showed the outgoing radiation type.
7. I fully observed the air temperature near and under the ground in summer within and without the persimmon orchard in the southwestern slope, and plainly showed the special character of the distribution of the temperature in the orchard