Search results for "ECHAM"

Enzimas: qué son y para qué sirven

2007

franco@uv.es

2015

Abstract. The convective transport module, CVTRANS, of the ECHAM/MESSy Atmospheric Chemistry (EMAC) model has been revised to better represent the physical flows and incorporate recent findings on the properties of the convective plumes. The modifications involve (i) applying intermediate time stepping based on a settable criterion, (ii) using an analytic expression to account for the intra-time-step mixing ratio evolution below cloud base, and (iii) implementing a novel expression for the mixing ratios of atmospheric compounds at the base of an updraft. Even when averaged over a year, the predicted mixing ratios of atmospheric compounds are affected considerably by the intermediate time st…

Potential predictability of crop impacting climate variables for East Africa and application to sorghum in the Mt Kenya area

2013

In Southern countries with rural low income populations, the vulnerability of rainfed agriculture to rainfall variability requires effective solutions to mitigate the effects of climatic hazards on crops. Predicting the characteristics of rainy seasons some time before they start should help the establishment of agricultural adaptation strategies to rainfall hazards. This is the objective of the present study, focused on East Africa (Kenya and northern Tanzania), and divided in three parts:- Define and document intra-seasonal descriptors (ISD) that will be considered in the predictability study. A new methodological approach has been developed in order to define the onset date (ORS) and the…

2019

Abstract. Recently, the aerosol microphysics submodel MADE3 (Modal Aerosol Dynamics model for Europe, adapted for global applications, third generation) was introduced as a successor to MADE and MADE-in. It includes nine aerosol species and nine lognormal modes to represent aerosol particles of three different mixing states throughout the aerosol size spectrum. Here, we describe the implementation of the most recent version of MADE3 into the ECHAM/MESSy Atmospheric Chemistry (EMAC) general circulation model, including a detailed evaluation of a 10-year aerosol simulation with MADE3 as part of EMAC. We compare simulation output to station network measurements of near-surface aerosol componen…

The 1-way on-line coupled model system MECO(n) – Part 4: Chemical evaluation (based on MESSy v2.52)

2016

Abstract. For the first time a simulation incorporating tropospheric and stratospheric chemistry using the newly developed MECO(n) model system is performed. MECO(n) is short for MESSyfied ECHAM and COSMO model nested n-times. It features an on-line coupling of the COSMO-CLM model, equipped with the Modular Earth Submodel System (MESSy) interface (called COSMO/MESSy), with the global atmospheric chemistry model ECHAM5/MESSy for Atmospheric Chemistry (EMAC). This on-line coupling allows a consistent model chain with respect to chemical and meteorological boundary conditions from the global scale down to the regional kilometre scale. A MECO(2) simulation incorporating one regional instance ov…

Earth System Chemistry integrated Modelling (ESCiMo) with the Modular Earth Submodel System (MESSy) version 2.51

2016

Abstract. Three types of reference simulations, as recommended by the Chemistry–Climate Model Initiative (CCMI), have been performed with version 2.51 of the European Centre for Medium-Range Weather Forecasts – Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model: hindcast simulations (1950–2011), hindcast simulations with specified dynamics (1979–2013), i.e. nudged towards ERA-Interim reanalysis data, and combined hindcast and projection simulations (1950–2100). The manuscript summarizes the updates of the model system and details the different model set-ups used, including the on-line calculated diagnostics. Simulations have been performed with two diff…

Trace gas composition in the Asian summer monsoon anticyclone: a case study based on aircraft observations and model simulations

2017

We present in situ measurements of the trace gas composition of the upper tropospheric (UT) Asian summer monsoon anticyclone (ASMA) performed with the High Altitude and Long Range Research Aircraft (HALO) in the frame of the Earth System Model Validation (ESMVal) campaign. Air masses with enhanced O3 mixing ratios were encountered after entering the ASMA at its southern edge at about 150 hPa on 18 September 2012. This is in contrast to the presumption that the anticyclone's interior is dominated by recently uplifted air with low O3 in the monsoon season. We also observed enhanced CO and HCl in the ASMA, which are tracers for boundary layer pollution and tropopause layer (TL) air or stratosp…

2018

Abstract. This study places HALO research aircraft observations in the upper-tropospheric Asian summer monsoon anticyclone (ASMA) into the context of regional, intra-annual variability by hindcasts with the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The observations were obtained during the Earth System Model Validation (ESMVal) campaign in September 2012. Observed and simulated tracer–tracer relations reflect photochemical O3 production as well as in-mixing from the lower troposphere and the tropopause layer. The simulations demonstrate that tropospheric trace gas profiles in the monsoon season are distinct from those in the rest of the year, and the measurements reflect the main proc…

Evaluation of the coupled high-resolution atmospheric chemistry model system MECO(n) using in situ and MAX-DOAS NO<sub>2</sub&am…

2021

Abstract. We present high spatial resolution (up to 2.2×2.2 km2) simulations focussed over south-west Germany using the online coupled regional atmospheric chemistry model system MECO(n) (MESSy-fied ECHAM and COSMO models nested n times). Numerical simulation of nitrogen dioxide (NO2) surface volume mixing ratios (VMRs) are compared to in situ measurements from a network with 193 locations including background, traffic-adjacent and industrial stations to investigate the model's performance in simulating the spatial and temporal variability of short-lived chemical species. We show that the use of a high-resolution and up-to-date emission inventory is crucial for reproducing the spatial varia…

Modeling the aerosol chemical composition of the tropopause over the Tibetan Plateau during the Asian summer monsoon

2019

Enhanced aerosol abundance in the upper troposphere and lower stratosphere (UTLS) associated with the Asian summer monsoon (ASM) is referred to as the Asian Tropopause Aerosol Layer (ATAL). The chemical composition, microphysical properties, and climate effects of aerosols in the ATAL have been the subject of discussion over the past decade. In this work, we use the ECHAM/MESSy Atmospheric Chemistry (EMAC) general circulation model at a relatively fine grid resolution (about 1.1×1.1∘) to numerically simulate the emissions, chemistry, and transport of aerosols and their precursors in the UTLS within the ASM anticyclone during the years 2010–2012. We find a pronounced maximum of aerosol extin…