2.1 Study on the influence of meteo-climatic characteristics of
the Himalayan area on the large-scale pollutants transport
Epson Meteo Centre (CEM), Cinisello Balsamo, Milano
Water Research Institute, National Research Council (IRSA/CNR), Brugherio, Milano
Principal investigators: Dr. Massimo Bollasina, Dr. Laura Bertolani, Dr. Gianni Tartari
Other researchers involved
Mr. Gian Pietro Verza - Ev-K²-CNR Committee, Bergamo
Col. Mario Giuliacci - Epson Meteo Centre (CEM)
Dr. Raffaele Salerno - Epson Meteo Centre (CEM)
Abstract
It is well known that the Himalayas play an important role within the Indian monsoon.
Thus, for meteorological and climate monitoring, it is very important to have
observational points located in such regions. Moreover, modelling studies are
fundamental for a better understanding of the mechanisms and the physics processes
related to the large-scale circulation of the monsoon. Finally, meteorological studies will
be directly connected to other environmental disciplines.
Introduction
This activity continues the research started in 1990 by the Water Research Institute
(IRSA) within the framework of the Ev-K²-CNR Project and, since 1998, carried out by a
research team called Pyramid MeteoGroup (PMG), a joint collaboration among the Ev-K2CNR Committee, the Epson Meteo Centre (CEM) and IRSA.
In 2002, the PMG has completed the installation of a network of Automated Weather
Stations (AWS) (called the Pyramid MeteoNetwork, PMN) along the Khumbu Valley,
Eastern Nepal. Meanwhile, the PMN has been integrated within the framework of the
Coordinated Enhanced Observing Period (CEOP) of the World Climate Research
Programme (WCRP) of the World Meteorological Organization (WMO) as a reference site
for the intensive observation of land-atmosphere interactions. For this purpose, the
Pyramid station has been implemented with sensors for the measurement of the
following parameters: upward/downward shortwave and longwave radiation, soil
moisture, soil temperature (at two depths), ground heat flux and snow depth. CEOP
aims to study and to document, for the three-year period 2002-2004, water and energy
fluxes at global scale and to investigate their influence on the global circulation of the
atmosphere.
The PMN is extremely useful as the stations are located in the region where the Indian
summer monsoon mostly impacts. The observations are useful to study monsoon
characteristics at different time scales (from intraseasonal to interdacadal variability).
Data collected since 1994 permitted to study not only local features but also large scale
characteristics in connection with data from general circulation models of the
atmosphere. In particular:

local climate has been characterised (onset/withdrawal mean dates, monsoon
precipitation characteristics, wind circulation, etc.);

the strong relation between local and large scale variability has been described
(active/break phases, biennial variability (the Tropospheric Biennial Oscillation)).
Moreover, since 2001, CEM has conducted modelling simulations of the Asian monsoon
by means of a general circulation model of the atmosphere (GCM) at two horizontal
resolutions (about 100 km and 200 km). In particular, sensitivity studies have been
carried out in order to study the role played by surface parameters, such as soil and
vegetation characteristics, during the onset and development of summer monsoon
circulation. The model is coupled with observed weekly sea surface temperature data.
Land surface parameters are updated daily with climatological data.
Finally, the research will be carried on developing relations with other environmental
disciplines.
Aims
The main aims of the research are:

to continue the participation to the CEOP Project and to continue the long term
monitoring of high altitude climate;

to create procedures for data quality verification, which involves sensor
maintenance and periodic parallel observations with other stations;

to study local circulation along the Khumbu Valley by means of data recorded by the
PMN;

to continue modelling studies of the monsoon circulation and its variability;

to study the transport and diffusion of pollutants at high altitudes;

to apply the results to other environmental disciplines, such as glaciology,
limnology, hydrology.
Data and Methods
The PMN consists of the following stations:

Pyramid 1 (5035 m), installed in 1990;

Pyramid 2 (5035 m), installed in 2000, implemented in 2002;

Pheriche (4260 m), installed in 2001;

Namche Bazaar (3570 m), installed in 2001 and belonging to the Sagarmatha
National Park;

Lukla (2660 m), installed in 2002.
The sensors installed measure the following parameters:
Pyramid, Pheriche, Namche e Lukla AWS
Parameter
Height of sensor (m)
Air Temperature
2
Precipitation
1.5
Relative Humidity
2
Atmospheric Pressure
2
Wind Velocity
5
Wind Direction
5
Global Solar Radiation
2
Pyramid AWS
Parameter
Height of sensor (m)
Ground Heat Flux
- 0.05
Soil Temperature
- 0.05; - 0.20
Snow Depth
2
Soil Moisture
- 0.05
Upward Shortwave Radiation
2
Downward Shortwave Radiation
2
Upward Longwave Radiation
2
Downward Longwave Radiation
2
Local climate characteristics will be investigated by means of:

hourly data recorded by the PMN;

hourly/daily data recorded by Syangboche station (3833 m).
Large-scale circulation will be investigated by means of:

daily/monthly gridded data for the latest years (NCEP/NCAR Reanalysis);

daily gridded data produced by the GCM simulations.
The new sensors implemented at the Pyramid station will permit to better study the
interactions between land and atmosphere, especially for what concerns heat and
moisture fluxes. These observations will be further implemented with new sensors to be
installed at different depths for a detailed description of the vertical profiles of soil
temperature and moisture.
Moreover, from 2004, upper air observations with sensors placed on a meteorological
tower (up to about 10 m) are expected to be conducted.
A portable station will be installed for test and sensor check.
The PMN will be managed following technical specifications which include: constant
check by Nepalese personnel, periodical sensor maintenance, data archive, etc.
Results
The main results expected are:

to document the diurnal cycle of the monsoon (convective precipitation,
mountain/valley wind system, etc.);

to study the response of atmospheric circulation to the variation of surface
parameters, such as soil moisture and temperature, snow cover, etc.;

to document the intraseasonal and interannual variability of the monsoon;

to study the interaction between local and large scale circulation;

to set up the modelling instruments for the study of the transport and diffusion of
pollutants.
The research will be carried on developing contacts with other international research
institutes, as is currently done within CEOP community. The Royal Nepalese Academy of
Science and Technology will be further involved in the activity. Moreover, high visibility
to Nepal people will be promoted. Detailed information on the research will be available
at the web site: http://news.epson.meteo.org
The main results will be published on international journals and presented to
conferences.
Activity in Italy for 2003-2005
Studies will be carried on following the main lines described above.
Activity in Nepal for 2003-2005
The following activities have been scheduled in Nepal:

training of local personnel for maintenance and check of the PMN;

definition of the collaboration with a Nepali Researcher;

diffusion of results at local institutes;

maintenance of the PMN;

comparative observation with a portable station;

installation of the new sensors at the Pyramid station.