HR: 0800h
AN: GC41A-0092    [Abstracts]
TI: Comparison of Surface Mountain Climate With Equivalent Free Air Parameters Extracted From NCEP/NCAR Reanalysis: Kilimanjaro, Tanzania.
AU: * Pepin, N C
EM: nicholas.pepin@port.ac.uk
AF: University of Portsmouth, Department of Geography, Buckingham Building, Lion Terrace, Portsmouth, PO1 3HE, United Kingdom
AU: Hardy, D
EM: dhardy@geo.umass.edu
AF: University of Massachussets, Department of Geosciences, Morrill Science Center, Amherst, MA 01003-9297, United States
AU: Duane, W
EM: bill_duane@yahoo.co.uk
AF: Universiti Brunei, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong, Bandar Seri Bagawan, BE 1410, Brunei Darussalam
AU: Losleben, M
EM: losleben@email.arizona.edu
AF: University of Arizona, National Phenology Network National Coordinating Office, Tucson, AZ 85719, United States
AB: It is difficult to predict future climate changes in areas of complex relief, since mountains generate their own climates distinct from the free atmosphere. Thus trends in climate at the mountain surface are different from those in the free air. We compare surface climate (temperature and vapour pressure) measured at seven elevations on the south-western slope of Kilimanjaro, the tallest free standing mountain in Africa, with equivalent observations in the free atmosphere from NCEP/NCAR reanalysis data for September 2004 to January 2006. Correlations between daily surface and free air temperature anomalies are greatest at low elevations below 2500 metres, meaning that synoptic (inter-diurnal) variability is the major control here. However, temperatures and moisture on the higher slopes above the treeline (3000 m) are decoupled from the free atmosphere, showing intense heating/cooling by day/night and import of moisture from lower elevations during the day. The lower forested slopes thus act as a moisture source, with large vapour pressure excesses reported in comparison with the free atmosphere (>5 hPa) which move upslope during daylight and subside downslope at night. Strong seasonal contrasts are shown in the vigour of the montane thermal circulation, but interactions with free air circulation (as represented by flow indices developed from reanalysis wind components) are complex. Upper air flow strength and direction (at 500 mb) have limited influence on surface heating and upslope moisture advection, which are dominated by the diurnal cycle rather than inter-diurnal synoptic controls. Thus local changes in surface characteristics (e.g. deforestation) could have a direct influence on the mountain climate of Kilimanjaro, making the upper slopes somewhat divorced from larger scale advective changes associated with global warming.
DE: 0350 Pressure, density, and temperature
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1637 Regional climate change
DE: 9305 Africa
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting