Browsing by Author "Flores, L.A."

Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Characteristics of low latitude backscatter from ionospheric E region and F region field-aligned irregularities obtained with the Piura VHF radar
    (Instituto Geofísico del Perú, 2003) Chau Chong Shing, Jorge Luis; Woodman Pollitt, Ronald Francisco; Flores, L.A.
    We present a summary ofthe characteristics of echoes from ionospheric (E and F region) field-aligned irregularities obtained with the Piura VHF radar (~7.0° dip latitude, outside the equatorial electrojet region). Our results are based on (1) intermittent monostatic observations made between 1991 and 1999, (2) continuous monostatic observations made between January 2000 and June 2001, and (3) intermittent interferometric observations since August 2001. Among other important results, we have found that the E-region echoes are stronger and occur more frequently during local summer. In addition, we have observed that the seasonal and daily occurrences of Piura F-region irregularities are similar to the occurrence oftopside ESF irregularities over Jicamarca.
    Palabras clave:F regionE regionRadar
  • Thumbnail Image
    ItemOpen Access
    Dendrochronological studies in the Peruvian north coast relate to ENSO
    (Instituto Geofísico del Perú, 2000) Rodríguez, R.; Mabres, A.; Flores, L.A.; Woodman Pollitt, Ronald Francisco
    Dendrochronological studies in the peruvian nort coast to find records of past El Niño - Southern Oscillation (ENSO) events began an the ale 80's. The peruvian north coast is the west-most area of South America, close to equator (05o S 80o W) and to the Sechura desert, is a very sensitive area to the climatic changes due to ENSO. An initial selection of several regional trees have been done for study. The study includes phenological observations and tree ring characteristics analysis as well as racial growth control of tree trunks and branches. The species more intensively studied and suitable to fina records due to the ENSO are Palo Santo, Hualtaco and Sapote.
    Palabras clave:El NiñoClimate changeAtmospheric precipitation
  • Thumbnail Image
    ItemOpen Access
    Observations of E region field-aligned irregularities just outside the equatorial electrojet region
    (Instituto Geofísico del Perú, Radio Observatorio de Jicamarca, 2000) Chau Chong Shing, Jorge Luis; Woodman Pollitt, Ronald Francisco; Flores, L.A.
    We have used the Piura VHF radar (5° 12’S, 80°38’W, ~7.5°N dip latitude), just outside the equatorial electrojet region, in northern Perú (see Figure 1) to gather echoes from 3-m E region field-aligned irregularities (FAI). Our observations are based on short campaigns of few consecutive days taken since 1995 at different times of the year. E region FAIs over Piura are confined to the 95-120 km altitude and present spectral characteristics similar to type 2 equatorial electrojet (EEJ) echoes. However, despite of being at only 7°N dip latitude, they appear mainly at nighttime and early morning, and thus do not present a temporal similarity to the EEJ. We observe the existence of two well-defined types of echoes: 1) lower E region echoes (95-105 km), and upper E region echoes (105-120 km). The lower echoes present a layering characteristic while the upper layer is more structured. In this latter region, the so-called quasiperiodic (QP) echoes have been observed with positive, vertical, and negative slopes and their characteristics are compared to those observed at mid latitudes. In addition, a relationship between concurrent E region irregularities over Piura and F region irregularities over Piura and Jicamarca is presented.
    Palabras clave:E RegionEquatorial ElectrojetEchoes