@article{GadelhaCoelhoXavieretal.2018,
  author    = {Gad{\^e}lha, Andr{\´e} N. and Coelho, Victor Hugo R. and Xavier, Alexandre C. and Barbosa, Lu{\´i}s Romero and Melo, Davi C. D. and Xuan, Yunqing and Huffman, George J. and Petersen, Walt A. and Almeida, Cristiano das Neves},
  title     = {Grid box-level evaluation of IMERG over Brazil at various space and time scales},
  series = {Atmospheric Research},
  volume    = {218},
  journal   = {Atmospheric Research},
  publisher = {Elsevier},
  address   = {New York},
  issn      = {0169-8095},
  doi       = {10.1016/j.atmosres.2018.12.001},
  pages     = {231 -- 244},
  year      = {2018},
  abstract  = {Rainfall data from the Global Precipitation Measurement (GPM) mission provide a new source of information with high spatiotemporal resolution that overcomes the limitations of ground-based rainfall information worldwide. This study evaluates the performance of the Integrated multi-satellitE Retrievals for GPM (IMERG) Final Run product over Brazil by means of multi-temporal and -spatial analyses. The assessment of the IMERG Final Run product is based on six statistics obtained for the period between January-December 2016 (daily, monthly, and annual basis). The analysis consisted of comparing the satellite-based estimates against a ground-based gridded rainfall product created using daily records from 4911 rain gauges distributed throughout Brazil. Overall, the results show that the IMERG product can effectively capture the spatial patterns of rainfall across Brazil. However, the IMERG product presents a slight tendency in overestimating the ground-based rainfall at all timescales. Furthermore, the performance of the satellite product varies throughout the region. The higher errors and biases are found in the North and Central-West regions, but the low density of rain gauges in those regions can be a source of large deviations between IMERG estimates and observations. A large underestimation of the IMERG data is evident along the coastal zone of the North-east region, probably due to the inability of the passive microwave and infrared sensors to detect warm-rain processes over land. This study shows that the IMERG product can be a good source of rainfall data to complement the ground precipitation measurements in most of Brazil, although some uncertainties are found and need to be further studied},
  language  = {en}
}
@article{BarbosadeLiraRabeloCoelhoetal.2019,
  author    = {Barbosa, Luis Romero and de Lira, Nicholas Borges and Rabelo Coelho, Victor Hugo and Bernard Passerat de Silans, Alain Marie and Gadelha, Andre Nobrega and Almeida, Cristiano das Neves},
  title     = {Stability of Soil Moisture Patterns Retrieved at Different Temporal Resolutions in a Tropical Watershed},
  series = {Revista brasileira de ciencias do solo},
  volume    = {43},
  journal   = {Revista brasileira de ciencias do solo},
  publisher = {Sociedade Brasileira de Ciencia do Solo},
  address   = {Vicosa},
  issn      = {0100-0683},
  doi       = {10.1590/18069657rbcs20180236},
  pages     = {21},
  year      = {2019},
  abstract  = {Above and underground hydrological processes depend on soil moisture (SM) variability, driven by different environmental factors that seldom are well-monitored, leading to a misunderstanding of soil water temporal patterns. This study investigated the stability of the SM temporal dynamics to different monitoring temporal resolutions around the border between two soil types in a tropical watershed. Four locations were instrumented in a small-scale watershed (5.84 km(2)) within the tropical coast of Northeast Brazil, encompassing different soil types (Espodossolo Humiluvico or Carbic Podzol, and Argissolo Vermelho-Amarelo or Haplic Acrisol), land covers (Atlantic Forest, bush vegetation, and grassland) and topographies (flat and moderate slope). The SM was monitored at a temporal resolution of one hour along the 2013-2014 hydrological year and then resampled a resolutions of 6 h, 12 h, 1 day, 2 days, 4 days, 7 days, and 15 days. Descriptive statistics, temporal variability, time-stability ranking, and hierarchical clustering revealed uneven associations among SM time components. The results show that the time-invariant component ruled SM temporal variability over the time-varying parcel, either at high or low temporal resolutions. Time-steps longer than 2 days affected the mean statistical metrics of the SM time-variant parcel. Additionally, SM at downstream and upstream sites behaved differently, suggesting that the temporal mean was regulated by steady soil properties (slope, restrictive layer, and soil texture), whereas their temporal anomalies were driven by climate (rainfall) and hydrogeological (groundwater level) factors. Therefore, it is concluded that around the border between tropical soil types, the distinct behaviour of time-variant and time-invariant components of SM time series reflects different combinations of their soil properties.},
  language  = {en}
}
@article{BarbosaAlmeidaRabeloCoelhoetal.2018,
  author    = {Barbosa, Luis Romero and Almeida, Cristiano das Neves and Rabelo Coelho, Victor Hugo and Freitas, Emerson da Silva and Galvao, Carlos de Oliveira and de Araujo, Jose Carlos},
  title     = {Sub-hourly rainfall patterns by hyetograph type under distinct climate conditions in Northeast of Brazil},
  series = {RBRH Revista Brasileira de Recursos H{\´i}dricos Brazilian Journal of Water Resources},
  volume    = {23},
  journal   = {RBRH Revista Brasileira de Recursos H{\´i}dricos Brazilian Journal of Water Resources},
  publisher = {Associa{\c{c}}{\~a}o Brasileira de Recursos H{\´i}dricos},
  address   = {Porto Alegre},
  issn      = {1414-381X},
  doi       = {10.1590/2318-0331.231820180076},
  pages     = {14},
  year      = {2018},
  abstract  = {The lack of process-based classification procedures may lead to unrealistic hyetograph design due to complex oscillation of rainfall depths when assimilated at high temporal resolutions. Four consecutive years of sub-hourly rainfall data were assimilated in three study areas (Guaraira, GEB, Sao Joao do Cariri, CEB, and Aiuaba, AEB) under distinct climates (very hot semi-arid and tropical wet). This study aimed to define rainfall events (for Minimum Inter-event Time, MIT, and Minimum Rainfall Depth, MRD, equal to 30 min and 1.016 mm, respectively), classify their hyetograph types (rectangular, R, unimodal with left-skewed, UL, right-skewed, UR, and centred peaks, UC, bimodal, B, and shapeless, SL), and compare their key rainfall properties (frequency, duration, depth, rate and peak). A rain pulse aggregation process allowed for reshaping SL-events for six different time spans varying from 2 to 30 min. The results revealed that the coastal area held predominantly R-events (64\% events and 49\% rainfall depth), in western semi-arid prevailed UL-events (57\% events and 63\% rainfall depth), whereas in eastern semi-arid mostly were R-events (61\% events and 30\% rainfall depth) similar to coastal area. It is concluded that each cloud formation type had important effects on hyetograph properties, differentiating them even within the same climate.},
  language  = {en}
}