Montávez, Juan Pedro

Person:
Montávez, Juan Pedro

Name

Montávez, Juan Pedro

publication.page.department

Universidad de Murcia. Departamento de Física

Full item page

Search Results

Now showing 1 - 7 of 7

Open Access
On the role of aerosols in the production of orographically-induced extreme rainfall in near-maritime environments
(Elsevier, 2022-01-04) Pravia-Sarabia, Enrique; Halifa Marín, Amar; Gómez Navarro, Juan José; Palacios-Pena, Laura; Jiménez Guerrero, Pedro; Montávez, Juan Pedro; Física; Facultad de Química
Open Access
On the spin-up period in WRF simulations over Europe: trade-offs between length and seasonality
(Wiley / American Geophysical Union, 2020-02-20) Jerez Rodríguez, Sonia; López Romero, José María; Turco, Marco; Lorente Plazas, Raquel; Gómez Navarro, Juan José; Jiménez Guerrero, Pedro; Montávez, Juan Pedro; Física; Facultades de la UMU::Facultad de Química; Facultades de la UMU::Facultad de Biología
Regional climate models (RCMs) are usually initialized and driven through the boundaries of their limited area domain by data provided by global models (GCMs). The mismatch between the low-resolution GCM initial conditions and RCM’s high resolution introduces physical inconsistencies between the various components of the RCM. These inconsistencies can be resolved by running the RCM during a period that is considered unreliable: the spin-up period. There is no deterministic definition of the length that the spin-up period should have. Here we try to provide general guidelines that can be used to the advantage of the community. We base our analysis on Weather Research and Forecasting (WRF) simulations over a Euro-Cordex compliant domain and find that for 2-m temperature and precipitation, rather short spin-up periods (1 week) can be sufficient. Nevertheless, longer periods (6 months) are advisable, and start dates in non-winter months should be pursued, as this ensures a more realistic representation of the snow cover. Thus, the issue is not only about the spin-up length. As the soil subsystem evolves slowly and requires longer periods to reach equilibrium than the longest considered here (1 year), seasonality plays an important role in minimizing the impact of the unreliability of the soil initialization. Fortunately, except for goals where the deep soil-atmosphere feedbacks are critical, the lack of equilibrium between them can be ignored, as it seems to have little effect on the simulation of the atmospheric variables most frequently used in RCM studies.
Open Access
TITAM (v1.0): the Time-Independent Tracking Algorithm for Medicanes
(Copernicus Publications, 2020-12-02) Pravia-Sarabia, Enrique; Gómez-Navarro, Juan José; Jiménez Guerrero, Pedro; Montávez, Juan Pedro; Física; Facultad de Química
This work aims at presenting TITAM, a time-independent tracking algorithm specifically suited for medicanes. In the last decades, the study of medicanes has been repeatedly addressed given their potential to damage coastal zones. Their hazardous associated meteorological conditions have converted them to a major threat. Even though medicane similarities to tropical cyclones have been widely studied in terms of genesis mechanisms and structure, the fact that the former appear in baroclinic environments, as well as the limited extension of the Mediterranean basin, makes them prone to maintaining their warm-cored and symmetric structure for short time periods. Thus, the usage of a measure for the warm-core nature of the cyclone, namely the Hart conditions, is a key factor for successful identification of a medicane. Furthermore, given their relatively small spatial extent, medicanes tend to appear embedded in or to coexist with larger lows. Hence, the implementation of a time-independent methodology, avoiding the search for a medicane based on its location at previous time steps, seems to be fundamental when facing situations of cyclone coexistence. The examples selected showcase how the algorithm presented throughout this paper is useful and robust for the tracking of medicanes. This methodology satisfies the requirements expected for a tracking method of this nature, namely the capacity to track multiple simultaneous cyclones, the ability to track a medicane in the presence of an intense trough inside the domain, the potential to separate the medicane from other similar structures by handling the intermittent loss of structure, and the capability to isolate and follow the medicane center regardless of other cyclones that could be present in the domain. The complete TITAM package, including preprocessing and post-processing tools, is available as free software extensively documented and prepared for its deployment. As a final remark, this algorithm sheds some light on medicane understanding regarding medicane structure, warm-core nature, and the existence of tilting.
Open Access
Assessing the effects of compound events of temperature and air pollution on weekly mortality in Spain using random forests
(Elsevier, 2025-10-18) Garnés-Morales, Ginés; Tortosa, Javier; Jiménez Guerrero, Pedro; Gil Guirado, Salvador; García Fernández, Esther; Montávez, Juan Pedro; Física
Open Access
Sensitivity of surface solar radiation to aerosol–radiation and aerosol–cloud interactions over Europe in WRFv3.6.1 climatic runs with fully interactive aerosols
(Copernicus Publications, 2021-03-17) Jerez Rodríguez, Sonia; Palacios-Peña, Laura; Gutiérrez, Claudia; Jiménez Guerrero, Pedro; López-Romero, Jose María; Pravia-Sarabia, Enrique; Montávez, Juan Pedro; Física; Facultad de Química
The amount of solar radiation reaching the Earth's surface can be highly determined by atmospheric aerosols, which have been pointed to as the most uncertain climate forcing agents through their direct (scattering and absorption), semi-direct (absorption implying a thermodynamic effect on clouds) and indirect (modification of cloud properties when aerosols act as cloud condensation nuclei) effects. Nonetheless, regional climate models hardly ever dynamically model the atmospheric concentration of aerosols and their interactions with radiation (ARIs) and clouds (ACIs). The objective of this work is to evince the role of modeling ARIs and ACIs in Weather Research and Forecast (WRF) model simulations with fully interactive aerosols (online resolved concentrations) with a focus on summer mean surface downward solar radiation (RSDS) over Europe. Under historical conditions (1991–2010), both ARIs and ACIs reduce RSDS by a few percentage points over central and northern regions. This reduction is larger when only ARIs are resolved, while ACIs counteract the effect of the former by up to half. The response of RSDS to the activation of ARIs and ACIs is mainly led by the aerosol effect on cloud coverage, while the aerosol effect on atmospheric optical depth plays a very minor role, which evinces the importance of semi-direct and indirect aerosol effects. In fact, differences in RSDS among experiments with and without aerosols are smaller under clear-sky conditions. In terms of future projections (2031–2050 vs. 1991–2010), the baseline pattern (from an experiment without aerosols) shows positive signals southward and negative signals northward. While ARIs enhance the former and reduce the latter, ACIs work in the opposite direction and provide a flatter RSDS change pattern, further evincing the opposite impact from semi-direct and indirect effects and the nontrivial influence of the latter.
Open Access
Precipitation response to aerosol–radiation and aerosol–cloud interactions in regional climate simulations over Europe
(Copernicus Publications, 2021-01-14) López-Romero, José María; Montávez, Juan Pedro; Jerez Rodríguez, Sonia; Lorente-Plaza, Raquel; Palacios-Peña, Laura; Jiménez Guerrero, Pedro; Física; Facultad de Química
The effect of aerosols on regional climate simulations presents large uncertainties due to their complex and non-linear interactions with a wide variety of factors, including aerosol–radiation (ARI) and aerosol–cloud (ACI) interactions. These interactions are strongly conditioned by the meteorological situation and type of aerosol, but, despite their increase, only a limited number of studies have covered this topic from a regional and climatic perspective. This contribution thus aims to quantify the impacts on precipitation of the inclusion of ARI and ACI processes in regional climate simulations driven by ERA20C reanalysis. A series of regional climatic simulations (for the period 1991–2010) for the Euro-CORDEX domain were conducted including ARI and ARI + ACI (ARCI), establishing as a reference a simulation where aerosols were not included interactively (BASE). The results show that the effects of ARI and ACI on time-mean spatially averaged precipitation over the whole domain are limited. However, a spatial redistribution of precipitation occurs when the ARI and ACI processes are introduced into the model, as well do changes in the precipitation intensity regimes. The main differences with respect to the base-case simulations occur in central Europe, where a decrease in precipitation is associated with a depletion in the number of rainy days and clouds at low level (CLL). This reduction in precipitation presents a strong correlation with the ratio PM2.5∕PM10, since the decrease is especially intense during those events with high values of that ratio (pointing to high levels of anthropogenic aerosols) over central Europe. The precipitation decrease occurs for all ranges of precipitation rates. On the other hand, the model produces an increase in precipitation over the eastern Mediterranean basin associated with an increase in clouds and rainy days when ACIs are implemented. Here, the change is caused by the high presence of PM10 (low PM2.5∕PM10 ratios, pointing to natural aerosols). In this case, the higher amount of precipitation affects only days with low rates of precipitation. Finally, there are some disperse areas where the inclusion of aerosols leads to an increase in precipitation, especially for moderate and high precipitation rates.
Open Access
Sensitivity of atmospheric rivers to aerosol treatment in regional climate simulations: insights from the AIRA identification algorithm
(Copernicus Publications [Commercial Publisher], 2024-02-19) Raluy López, Eloisa; Montávez, Juan Pedro; Jiménez Guerrero, Pedro; Física
This study analyzed the sensitivity of atmospheric rivers (ARs) to aerosol treatment in regional climate simulations. Three experiments covering the Iberian Peninsula for the period from 1991 to 2010 were examined: (1) an experiment including prescribed aerosols (BASE); (2) an experiment including direct and semi-direct aerosol effects (ARI); and (3) an experiment including direct, semi-direct, and indirect aerosol effects (ARCI). A new regional-scale AR identification algorithm, AIRA, was developed and used to identify around 250 ARs in each experiment. The results showed that spring and autumn ARs were the most frequent, intense, and long-lasting and that ARs could explain up to 30 % of the total accumulated precipitation. The inclusion of aerosols was found to redistribute precipitation, with increases in the areas of AR occurrence. The analysis of common AR events showed that the differences between simulations were minimal in the most intense cases and that a negative correlation existed between mean direction and mean latitude differences. This implies that more zonal ARs in ARI or ARCI with respect to BASE could also be linked to northward deviations. The joint analysis and classification of dust and sea salt aerosol distributions allowed for the common events to be clustered into eight main aerosol configurations in ARI and ARCI. The sensitivity of ARs to different aerosol treatments was observed to be relevant, inducing spatial deviations and integrated water vapor transport (IVT) magnitude reinforcements/attenuations with respect to the BASE simulation depending on the aerosol configuration. Thus, the correct inclusion of aerosol effects is important for the simulation of AR behavior at both global and regional scales, which is essential for meteorological predictions and climate change projections.