EXAMINATION OF SOME SINGULAR EVENTS

200

100

VI

VII

VIII

Figure 14. Mean northsouth cross sections of mean surface air temperature, with a terrain cross

section for reference. The morning air temperatures are stratified by snow depth and elevation

structure. The envelopes associated with maximum and minimum snow depth are plotted to guide

the eye.

difference subsets observed along the 30 km

We established, in Part I, that the temperature

northsouth observation path from P to L dis-

difference along the river plane was less than

1.6C over 30 km in 84% of observations. Figure

cussed in Part I. The mean temperature differ-

ences, with respect to the temperature at P, were

14 indicates that several small basins at slightly

calculated for these data subsets. Cross-sectional

higher elevation had morning air temperature dif-

analyses of the mean temperature differences, in-

ferences quite similar to points along the river

cluding the near river points for which frequency

plane. Temperature difference along the slope

distributions were given in Part I, are shown in

south of S was greater than that in those basins

Figure 14. Coordinating symbols are again noted

(V, VI, VII, and VIII). This difference is similar to

on the topographic cross section.

the slope basin temperature difference on the

Under lapse structure, air temperatures along

slopes connecting basins II, I, and the apex of

this transect are related to the temperature at the

observation, A. These temperature differences gen-

bridge P by the lapse rate. Because of the narrow

erally conform to the slope and basin theories of

range of temperature differences, only those mea-

Magono et al. (1982) and Maki et al. (1986). It does

sured with sparse snow cover (<3 cm) and com-

appear that depth and continuity of snow cover

plete snow cover (>30 cm) are plotted. These

may be additional variables influencing the morn-

points are connected to form an envelope to guide

ing temperature on slopes and in basins.

the reader. All other temperature differences un-

der lapse are enclosed in the plotted envelope.

This small temperature difference necessitated use

EXAMINATION OF

of mean values in this analysis.

SOME SINGULAR EVENTS

The temperature differences at these places are

much greater under inversion. All mean morning

The experiments, observations, and theories

temperature differences corresponding to the

describing winter slope and basin temperatures

snow cover categories are plotted at each obser-

in Hokkaido were primarily formulated to ex-

vation point. The envelope lines of the sparse and

plain the extremely cold air that occurred on a

total snow cover classes are again plotted to aid

few days. Hokkaido has very volcanic topogra-

in estimating the range of variation.

phy, and most of the work of Magono et al. (1982)

18