Browsing by Author "Martínez-Castro, Daniel"
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Item Open Access Assessment of CMIP6 performance and projected temperature and precipitation changes over South America(Springer, 2021-06-17) Almazroui, Mansour; Ashfaq, Moetasim; Islam, M. Nazrul; Rashid, Irfan Ur; Kamil, Shahzad; Abid, Muhammad Adnan; O’Brien, Enda; Ismail, Muhammad; Reboita, Michelle Simões; Sörensson, Anna A.; Arias, Paola A.; Alves, Lincoln Muniz; Tippett, Michael K.; Saeed, Sajjad; Haarsma, Rein; Doblas‑Reyes, Francisco J.; Saeed, Fahad; Kucharski, Fred; Nadeem, Imran; Silva Vidal, Yamina; Rivera, Juan A.; Ehsan, Muhammad Azhar; Martínez-Castro, Daniel; Muñoz, Ángel G.; Ali, Md. Arfan; Coppola, Erika; Sylla, Mouhamadou BambaWe evaluate the performance of a large ensemble of Global Climate Models (GCMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) over South America for a recent past reference period and examine their projections of twenty-first century precipitation and temperature changes. The future changes are computed for two time slices (2040–2059 and 2080–2099) relative to the reference period (1995–2014) under four Shared Socioeconomic Pathways (SSPs, SSP1–2.6, SSP2–4.5, SSP3–7.0 and SSP5–8.5). The CMIP6 GCMs successfully capture the main climate characteristics across South America. However, they exhibit varying skill in the spatiotemporal distribution of precipitation and temperature at the sub-regional scale, particularly over high latitudes and altitudes. Future precipitation exhibits a decrease over the east of the northern Andes in tropical South America and the southern Andes in Chile and Amazonia, and an increase over southeastern South America and the northern Andes—a result generally consistent with earlier CMIP (3 and 5) projections. However, most of these changes remain within the range of variability of the reference period. In contrast, temperature increases are robust in terms of magnitude even under the SSP1–2.6. Future changes mostly progress monotonically from the weakest to the strongest forcing scenario, and from the mid-century to late-century projection period. There is an increase in the seasonality of the intra-annual precipitation distribution, as the wetter part of the year contributes relatively more to the annual total. Furthermore, an increasingly heavy-tailed precipitation distribution and a rightward shifted temperature distribution provide strong indications of a more intense hydrological cycle as greenhouse gas emissions increase. The relative distance of an individual GCM from the ensemble mean does not substantially vary across different scenarios. We found no clear systematic linkage between model spread about the mean in the reference period and the magnitude of simulated sub-regional climate change in the future period. Overall, these results could be useful for regional climate change impact assessments across South America.Item Restricted Evaluation of GPM Dual-Frequency Precipitation Radar algorithms to estimate drop size distribution parameters, using ground-based measurement over the Central Andes of Peru(Springer, 2021-09) Del Castillo-Velarde, Carlos; Kumar, Shailendra; Valdivia Prado, Jairo Michael; Moya Álvarez, Aldo Saturnino; Flores Rojas, José Luis; Villalobos Puma, Elver Edmundo; Martínez-Castro, Daniel; Silva Vidal, YaminaThe raindrop size distribution (DSD) parameters, which consists of the mass-weighted average diameter (Dm) and the scaling parameter for the concentration (Nw) are essential to estimate precipitation in numerical modelling and other research areas such as the Global Precipitation Measurement (GPM) core satellite. In the present work, we used the GPM Dual-Frequency Precipitation Radar algorithms (GPM-DPR), single (SF) and dual (DF) frequency, and in situ observations to derive the DSD parameters and evaluate the performance of algorithms under the complex orography and climate regime of the central Andes. We used data from optical disdrometer and Ka-band profiler radar over Huancayo Observatory during the austral summer monsoon. Our results indicate that the GPM-DPR algorithms have problems to correctly estimate the DSD parameters of convective rains due to the high variability in time and space of this type of rain and is the result of fixing the shape parameter (µ). The estimation of DSD parameters in stratiform rains, which are very common in the central Andes, is strongly affected by the limitation of the DF algorithm in light rain rates caused by its inability to estimate Dm < 1 mm.Item Open Access El impacto de la parametrización de procesos microfísicos en la simulación de dos eventos de lluvia convectiva sobre los Andes centrales del Perú usando el modelo numérico WRF-ARW(Instituto Geofísico del Perú, 2020-09) Martínez-Castro, Daniel; Kumar, Shailendra; Flores Rojas, José Luis; Moya Álvarez, Aldo Saturnino; Valdivia Prado, Jairo Michael; Villalobos Puma, Elver Edmundo; Del Castillo Velarde, Carlos; Silva Vidal, YaminaEl presente estudio explora el impacto del método de expresar los procesos microfísicos en las nubes en la simulación numérica de eventos de lluvia convectiva sobre los Andes centrales, utilizando el modelo numérico de Investigación y Pronóstico del Tiempo (WRF, por sus siglas en inglés). Se probaron seis métodos de parametrización de los procesos microfísicos, a partir de la anidación sucesiva unidireccional de cuatro dominios (18, 6, 3 y 0.75 km de resolución). Las parametrizaciones de otros procesos físicos se mantuvieron invariables en los diferentes experimentos. Se integró durante 36 h con los datos globales del Centro Nacional de Predicción Ambiental de Estados Unidos (NCEP, por sus siglas en inglés) con condiciones iniciales de las 07:00, hora local (GMT-5). Las simulaciones se verificaron utilizando datos de satélite GOES, información del radar perfilador de nubes de banda Ka instalado en el Observatorio de Huancayo y variables meteorológicas medidas en superficie. Todas las parametrizaciones microfísicas describieron aproximadamente el comportamiento de la temperatura durante el paso del sistema, aunque en uno de los casos se subestimó la temperatura y en otros dos se subestimó la precipitación acumulada en 24 h. En particular, las configuraciones del modelo con parametrizaciones de Morrison y Lin reprodujeron la dinámica general del desarrollo de los sistemas de nubes para los dos estudios de caso. No obstante, el análisis del campo horizontal y los perfiles verticales de la masa de agua del sistema, así como los diferentes hidrometeoros muestran que la parametrización de Morrison reprodujo los sistemas convectivos de manera más consistente con las observaciones que los otros métodos.Item Restricted On the dynamic mechanisms of intense rainfall events in the central Andes of Peru, Mantaro valley(Elsevier, 2021-01-15) Flores Rojas, José Luis; Moya Álvarez, Aldo Saturnino; Valdivia Prado, Jairo Michael; Piñas-Laura, Manuel; Kumar, Shailendra; Karam, Hugo Abi; Villalobos Puma, Elver Edmundo; Martínez-Castro, Daniel; Silva Vidal, YaminaThe present study was aimed at analysing the main atmospheric dynamic mechanisms associated with the occurrence of intense rainfall events above the Huancayo observatory (12.05°S, 75.32°W, 3313 m asl) in the central Andes of Perú (Mantaro valley) from January 2018 to April 2019. To identify the rainfall events, we used a set of instruments from the laboratory of physics, microphysics and radiation (LAMAR) composed by in-situ pluviometric observations, satellite remote sensing data (GPM), Cloud Radar (MIRA-35c), Boundary Layer Tropospheric Radar (BLTR) and downscaling model simulations with WRF (resolutions: 18 km, 6 km and 2 km) and ARPS (0.5 km) models to analyse the dynamics of the atmosphere for the synoptic, meso and local processes that control the occurrence of these rainfall events. The results showed that all intense rainfall events are associated with the presence of thermal meso-scale circulations that transport moisture fluxes through passes with gentle slopes along both sides of the Andes. The easterly moisture fluxes come in from the South America Low Level Jet (SALLJ) and the westerly moisture fluxes from the Pacific Ocean. The arrival of these moisture flows to regions within the Mantaro valley depends on their coupling with the circulations at medium and high levels of the atmosphere. At the synoptic scale, the results show that the rainfall events can be separated into two groups: the first one associated with westerly circulations (WC) at the mid and upper levels of the atmosphere, generated by the weakening and eastern displacement of the anticyclonic Bolivian high-North east low (BH-NE) system, and the second associated with easterly circulations (EC) at the mid and upper levels of the atmosphere, generated by the intensification of the BH-NE system. The observed and simulated results showed that multicell convective systems of WC events are more extensive and deeper than EC events. This situation can be explained as the convergence of moisture fluxes from opposite directions occurred within the Mantaro basin for WC events. In contrast, for EC events, the convergence develops at the east Andes mountain range, following which the multicell storm system propagates westward, driven by easterly circulations. The EC events occur mostly in the summer months, while the WC events occur mostly in the autumn and spring months. Moreover, apparently the inertia gravity waves (IGWs) formed in the Amazon basin transport moisture and energy to the central Andes plateau and intensify the convection processes.Item Restricted Spatial and Temporal Distribution of Black Carbon in Peru from the Analysis of Biomass Burning Sources and the Use of Numerical Models(Springer, 2023-06) Moya-Álvarez, Aldo S.; Estevan, René; Martínez-Castro, Daniel; Silva Vidal, YaminaThe spatial and temporal distribution of biomass burning in Peru and neighboring countries was analyzed during the 2018–2020 period, with emphasis on 2019. To determine the glaciers most affected by BC as a consequence of vegetation burning, simulations were carried out with the WRF-CHEM model, and to diagnose the origin of BC particles received by the Huaytapallana glacier, backward trajectories were built with the HYSPLIT model. It was found that, during the studied period, the burning of biomass emitted large amounts of BC into the atmosphere, while the number of fires in Peru began its most notable increase in the month of July, with maxima between August and September. Comparisons of the number of outbreaks with the Aerosol Optical Depth (AOD) measured at the Huancayo observatory showed a significant correlation. The Ucayali region is the one that contributes the greatest number of outbreaks and the greatest emissions are produced in the south of Loreto. The WRF model showed that the concentrations in July are still low in relation to the August–October period. The mountain ranges that received the greatest impact from BC emissions were Huaytapallana, Huagoruncho, and Vilcabamba. BC transport is mainly oriented from north to south, moving the particles from the areas of greatest burning to the glaciers located in the center and south of the country. BC concentrations over the Cordillera Blanca were lower. The diagnosis of the backward trajectories corroborated the results of WRF-CHEM and showed trajectories mostly from the north.Item Open Access The impact of microphysics parameterization in the simulation of two convective rainfall events over the Central Andes of Peru using WRF-ARW(MDPI, 2019-08-01) Martínez-Castro, Daniel; Kumar, Shailendra; Flores Rojas, José Luis; Moya Álvarez, Aldo Saturnino; Valdivia Prado, Jairo Michael; Villalobos Puma, Elver Edmundo; Del Castillo Velarde, Carlos; Silva Vidal, YaminaThe present study explores the cloud microphysics (MPs) impact on the simulation of two convective rainfall events (CREs) over the complex topography of Andes mountains, using the Weather Research and Forecasting- Advanced Research (WRF-ARW) model. The events occurred on December 29 2015 (CRE1) and January 7 2016 (CRE2). Six microphysical parameterizations (MPPs) (Thompson, WSM6, Morrison, Goddard, Milbrandt and Lin) were tested, which had been previously applied in complex orography areas. The one-way nesting technique was applied to four domains, with horizontal resolutions of 18, 6, and 3 km for the outer ones, in which cumulus and MP parameterizations were applied, while for the innermost domain, with a resolution of 0.75 km, only MP parameterization was used. It was integrated for 36 h with National Centers for Environmental Prediction (NCEP Final Operational Global Analysis (NFL) initial conditions at 00:00 UTC (Coordinated Universal Time). The simulations were verified using Geostationary Operational Environmental Satellites (GOES) brightness temperature, Ka band cloud radar, and surface meteorology variables observed at the Huancayo Observatory. All the MPPs detected the surface temperature signature of the CREs, but for CRE2, it was underestimated during its lifetime in its vicinity, matching well after the simulated event. For CRE1, all the schemes gave good estimations of 24 h precipitation, but for CRE2, Goddard and Milbrandt underestimated the 24 h precipitation in the inner domain. The Morrison and Lin configurations reproduced the general dynamics of the development of cloud systems for the two case studies. The vertical profiles of the hydrometeors simulated by different schemes showed significant differences. The best performance of the Morrison scheme for both case studies may be related to its ability to simulate the role of graupel in precipitation formation. The analysis of the maximum reflectivity field, cloud top distribution, and vertical structure of the simulated cloud field also shows that the Morrison parameterization reproduced the convective systems consistently with observations.