In the present work we estimate the aerosols optical thickness (AOT) in the wavelength of 0.55µm using the mod021km - level 1B Calibrated Radiances - 1km images as input of the SBDART radiative transfer model [1]. The study area is Peru in the geographic latitudes 0 to 20°S and the geographic longitudes of 82 to 68°O. The SBDART model simulates the radiative transfer in the atmosphere (scattering, absorption, emission, etc.), estimating the irradiance in the top of the atmosphere and on the Earth surface. The two-stream and Eddington approximations are used to solve the radiative transfer equation, considering a parallel plane atmosphere. This model generate equations defining the AOT of 0.55µm as a function of the reflectance at the top of the atmosphere (TOA) for the band 1 at 0.66µm of the MODIS sensor.The 0.55 µm AOT estimated by the SBDART model was verify with the 0.55µm A...

In this work, we identify soil degradation by salinity, using images of HRG-2 (SPOT), TM and ETM+ (LANDSAT) of high spatial resolution in the sugarcane crops of Empresa Agroindustrial de Pomalca, located in the Lambayeque Region at the north coast of Peru. The reflectance of the surface soil, normalized difference vegetation index, NDVI, and salinity index, IndSal, was estimated from the satellite images using the image processing software ENVI 4.5, and the programming language IDL.Also, the maximum compound values of the NDVI and IndSal was determined from the TM and ETM+ images to identify soils with low farming quality and degraded soils by salinity. To estimate the salinity in the sugarcane farming, we performed, by graphics, the correlation between the soil electrical conductivity, CE, and the spectral reflectance values extracted from the B1, B2, B3 and B4 (TM-20/04/2008) bands ...

An initial ground validation of the Integrated Multisatellite Retrievals for GPM (IMERG) Day-1 product from March 2014 to August 2015 is presented for the tropical Andes. IMERG was evaluated along with the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) against 302 quality-controlled rain gauges across Ecuador and Peru. Detection, quantitative estimation statistics, and probability distribution functions are calculated at different spatial (0.1°, 0.25°) and temporal (1 h, 3 h, daily) scales. Precipitation products are analyzed for hydrometeorologically distinct subregions. Results show that IMERG has a superior detection and quantitative rainfall intensity estimation ability than TMPA, particularly in the high Andes. Despite slightly weaker agreement of mean rainfall fields, IMERG shows better characterization of gauge observations when separatin...

This research was funded by the European Institute of Technology (EIT)Climate Knowledge and Innovation Community (Climate-KIC). Buytaert received support from the Ecuadorian PROMETEO program during part of this research. Buytaert and Zulkafli received support from UK NERC grant NE-K010239-1. Willems and Robles received support from Proyecto Cátedra CONCYTEC: “Teledetección en la Desertificación y Sequía.” Gauge data were obtained from HYBAM (http://www.ore-hybam.org) and NOAA NCDC (http://www.ncdc.noaa.gov/cdo-web) as well as from the national weather services of Bolivia (SENAMHI), Colombia (IDEAM), Ecuador (INAMHI), and Peru (SENAMHI), which are not freely accessible in the public domain but can be requested from the institutions. TRMM 2A25 data were obtained from NASA via the Precipitation Processing System (http://pps.gsfc.nasa.gov). The authors would like to thank Bodo Bookha...

Satellite precipitation products are becoming increasingly useful to complement rain gauge networks in regions where these are too sparse to capture spatial precipitation patterns, such as in the Tropical Andes. The Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (TPR) was active for 17 years (1998–2014) and has generated one of the longest single-sensor, high-resolution, and high accuracy rainfall records. In this study, high-resolution (5 km) gridded mean monthly climatological precipitation is derived from the raw orbital TPR data (TRMM 2A25) and merged with 723 rain gauges using multiple satellite-gauge (S-G) merging approaches. The resulting precipitation products are evaluated by cross validation and catchment water balances (runoff ratios) for 50 catchments across the Tropical Andes. Results show that the TPR captures major synoptic and seasonal precipitation patt...