Author(s): Pedro Rau; Thomas Condom; Waldo Lavado
Linked Author(s): Pedro Rau
Keywords: Temperature; Trends; NCEP NCAR reanalysis; Andes
Abstract: Understanding the climate dynamics in mountainous areas still remains a challenge. For Peruvian areas situated above 3000 m three aspects concerning the temperatures are developed with in-situ and NCEP NCAR Reanalysis from National Center for Environmental Prediction and National Center for Atmospheric Research (NNR) data: a) Based on in-situ temperature records of about 30 years for 27 stations, no trend was identified at 99% of confidence level in the Northern Andes (Cordillera Blanca y Negra) of Peru, contrary to regions in the south of Central Andes of Peru where it was identified local trends in the Andean valleys near to Vilcanota node with maximum values of 0. 03_o_C/year. b) Taking into account the importance of temperature and data scarcity in mountainous regions, in-situ records were compared with other data source such as NNR. The comparison was made according to the geographical location, the common periods of the records and grid coverage. We conclude that NNR at 700 hPa level (~3000 m asl) and 600 hPa level (~4000 m asl) offer an approximation to terrain elevation of stations, however that comparison has variations from 10°C in Northern Andes to 0. 4°C in Central Andes. c) Considering the differences between in-situ and NNR data, a correction of NNR data is proposed with monthly regional lapse rate. The methodology considers the use of one base in-situ station into a NNR grid with an altitudinal gradient, thus we generate mean monthly temperatures records in other areas into the NNR grid. The reliability of corrections are evaluated is terms of the correlation coefficient and the root mean squared error and the results offer very acceptable results in Northern and Central Andes.
Year: 2013