DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.20140#0583
TYPE OF THE ISOTHERMAL LINES IN THE PROFILES
OF HIGH ASIA.
The numerical elements and the decrease of temperature being detailed, the analysis
of the form of the lines in the Plate of profiles will best make apparent what is
peculiar to High Asia when compared with other mountain systems, and what may
be considered a law of a more general character.
I. Heating influence of India.
The first modification presenting itself in the isothermal profiles, and alluded to
already, is, that the southern slopes of the Himalayan borders facing India are too
warm throughout the year in consequence of ascending currents of heated air.
The annual isothermal lines of 74-5°, 74°, and 73° Fahr., which, in the map of
Plate IV. present themselves as running on the sea-level under the greatest part of
the outer ranges of the Himalaya, are objects of reference the more decisive as they
are but the junction of the stations to the west and east of the Himalaya in the
Panjab and Assam,1 and unaffected therefore by the influence of descending currents,
somewhat modifying, as we shall see in Hindostan and Bengal.
In the isothermal lines of the profiles the gradual change in the steepness of these
curvatures with the elevation is proportional to the diminishing of the influence of the
1 Unless I obtained these fundamental dotted lines the comparison of different stations for deducing the decrease
would have been very insufficient, since it would have remained arbitrary how to correct the effect of latitude. Even
Patna combined with Kathmandu, or Rampur Boleah with Darjiling, as easily seen from the map of the isothermal
lines, would give a decrease much too rapid, Patna and Rampur being 77 -8° Fahr. in the mean of the year, and
the basis below Kathmandu and Darjiling only 75° to 74'6° Fahr.
OF HIGH ASIA.
The numerical elements and the decrease of temperature being detailed, the analysis
of the form of the lines in the Plate of profiles will best make apparent what is
peculiar to High Asia when compared with other mountain systems, and what may
be considered a law of a more general character.
I. Heating influence of India.
The first modification presenting itself in the isothermal profiles, and alluded to
already, is, that the southern slopes of the Himalayan borders facing India are too
warm throughout the year in consequence of ascending currents of heated air.
The annual isothermal lines of 74-5°, 74°, and 73° Fahr., which, in the map of
Plate IV. present themselves as running on the sea-level under the greatest part of
the outer ranges of the Himalaya, are objects of reference the more decisive as they
are but the junction of the stations to the west and east of the Himalaya in the
Panjab and Assam,1 and unaffected therefore by the influence of descending currents,
somewhat modifying, as we shall see in Hindostan and Bengal.
In the isothermal lines of the profiles the gradual change in the steepness of these
curvatures with the elevation is proportional to the diminishing of the influence of the
1 Unless I obtained these fundamental dotted lines the comparison of different stations for deducing the decrease
would have been very insufficient, since it would have remained arbitrary how to correct the effect of latitude. Even
Patna combined with Kathmandu, or Rampur Boleah with Darjiling, as easily seen from the map of the isothermal
lines, would give a decrease much too rapid, Patna and Rampur being 77 -8° Fahr. in the mean of the year, and
the basis below Kathmandu and Darjiling only 75° to 74'6° Fahr.