A5068066429- Climate variability and models
- Meteorological Phenomena and Simulations
- Urban Heat Island Mitigation
- Wind and Air Flow Studies
- Fluid Dynamics and Turbulent Flows
- Tropical and Extratropical Cyclones Research
- Computational Fluid Dynamics and Aerodynamics
- Remote Sensing and Land Use
- Precipitation Measurement and Analysis
- Fluid Dynamics and Vibration Analysis
- Plant Water Relations and Carbon Dynamics
- Atmospheric and Environmental Gas Dynamics
- Cryospheric studies and observations
- Land Use and Ecosystem Services
- Geophysics and Gravity Measurements
- Model Reduction and Neural Networks
- Urban Green Space and Health
- Gas Dynamics and Kinetic Theory
- Ocean Waves and Remote Sensing
- Arctic and Antarctic ice dynamics
- Radio Wave Propagation Studies
- Orbital Angular Momentum in Optics
- Optical Wireless Communication Technologies
- Sports Dynamics and Biomechanics
- Climate Change and Sustainable Development
ETH Zurich
2021-2024
Meteorological Service Singapore
2019-2022
Institute of Atmospheric Sciences and Climate
2021-2022
Max Planck Society
2016
Max Planck Institute for Meteorology
2013-2016
Sorbonne Université
2007-2009
Institut Jean Le Rond d'Alembert
2009
Centre National de la Recherche Scientifique
2007-2009
Indian Institute of Technology Kanpur
2004-2007
Large‐eddy simulations (LES) with the new ICOsahedral Non‐hydrostatic atmosphere model (ICON) covering Germany are evaluated for four days in spring 2013 using observational data from various sources. Reference established Consortium Small‐scale Modelling (COSMO) numerical weather prediction and further standard LES codes performed used as a reference. This comprehensive evaluation approach covers multiple parameters scales, focusing on boundary‐layer variables, clouds precipitation. The...
Abstract ICON (ICOsahedral Nonhydrostatic) is a unified modeling system for global numerical weather prediction (NWP) and climate studies. Validation of its dynamical core against test suite forecasting has been recently published by Zängl et al. (2014). In the present work, an extension presented that enables it to perform as large eddy simulation (LES) model. The details implementation LES turbulence scheme in are explained cases performed validate two standard models. Despite limitations...
Abstract The parameterization of shallow cumuli across a range model grid resolutions kilometre‐scales faces at least three major difficulties: (1) closure assumptions conventional schemes are no longer valid, (2) stochastic fluctuations become substantial and increase with resolution, (3) convective circulations that emerge on the grids under‐resolved grid‐scale dependent. Here we develop cumulus clouds to address first two points, study how this interacts in case over ocean. We couple...
Abstract Understanding the response of extreme precipitation (EP) at a city scale to global warming is critical reducing respective risk urban flooding. Yet, current knowledge on this issue limited. Here, focusing an agglomeration in tropics, Singapore, we reveal that future enhances both frequency and intensity EP, based simulations with state‐of‐the‐art convection‐permitting regional climate model. EP intensification can reach maximum “super” Clausius‐Clapeyron rate ( +7% per K warming)...
Vortex shedding behind a cylinder can be controlled by placing another small it, at low Reynolds numbers. This has been demonstrated experimentally Strykowski & Sreenivasan ( J. Fluid Mech . vol. 218, 1990, p. 74). These authors also provided preliminary numerical results, modelling the control innovative application of boundary conditions on some selective nodes. There are no other computational and theoretical studies that have explored physical mechanism. In present work, using an...
Abstract The horizontal grid spacing of numerical weather prediction models keeps decreasing towards the hectometric range. We perform limited‐area simulations with Icosahedral Nonhydrostatic (ICON) model across spacings (1 km, 500 m, 250 125 m) in Inn Valley, Austria, and evaluate observations from Cross‐Valley Flow Valley Investigated by Dual‐Doppler LIDAR Measurements (CROSSINN) measurement campaign. This allows us to investigate whether increasing resolution automatically improves...
Abstract There is still no consensus on the mechanisms that modify precipitation over and around cities, especially for those located in tropics where convective processes primarily drive rainfall. Here we contribute to ongoing discussion about urban‐associated by investigating urban effect diurnal cycle of rainfall Singapore. We use version numerical weather prediction system Meteorological Service Singapore (hereafter called uSINGV) at a 300 m horizontal resolution simulate conditions its...
Abstract A tropical version of the high‐resolution (300 m) UK Met Office forecast model (UM) using MORUSES urban canopy parametrization (UCP) is adapted for Singapore. High‐resolution surface parameters are determined a methodology based on Voronoi polygons applied to 3D building database. The evaluated clear sky and calm conditions at neighbourhood scale by comparing its predictions with two sources observations: energy balance data from an eddy covariance flux tower located in low‐rise...
Abstract Numerical weather prediction (NWP) capabilities in the Maritime Continent are not as developed midlatitudes. Countries region do develop their own modelling systems; rather they adapt models primarily for Due to complexity of processes involved region, this adaptation is non‐trivial. In article developments made by Meteorological Service Singapore (MSS) and United Kingdom Met Office (UKMO) implement a convective‐scale NWP system short‐range surrounding regions presented. particular,...
Abstract Simulations of five November months (2010–2014) using the urban version numerical weather prediction system Meteorological Service Singapore (uSINGV) are used to analyse effect on convective precipitation over and Johor Bahru (Malaysia). The model is able closely predict locations where rainfall peaks occur, but totals overestimated compared radar data. temporal variability in region shows that areas increase frequency severity events such impact increases with intensity. Results...
Trajectory of an optical vortex has been identified for its propagation in atmospheric turbulence using numerical simulations. An analytical expression found, relating the radial departure plane perpendicular to direction propagation, refractive index structure function parameter and inner scale turbulence. The angular orientation same transverse is found be related anisotropy medium. obtained results provide alternative way find turbulent parameters with help vortices.
Abstract Biases in simulating the diurnal cycle of convection near western coast island Sumatra have been investigated using data from pilot field campaign Years Maritime Continent (pre-YMC). The was carried out at a sea [Research Vessel (R/V) Mirai] and land (Bengkulu, Sumatra) site. Simulations are performed tropical configuration Met Office model grid resolution 1.5 km limited-area mode. focus this study is to understand how biases input conditions ECMWF high-resolution deterministic...
Extreme rainfall is one of the primary meteorological hazards in Singapore, as well elsewhere deep tropics, and it can lead to significant local flooding. Since 2013, Meteorological Service Singapore (MSS) United Kingdom Met Office (UKMO) have been collaborating develop a convective-scale Numerical Weather Prediction (NWP) system, called SINGV. Its aim provide improved weather forecasts for surrounding region, with focus on short-range prediction localized heavy rainfall. This paper provides...
Abstract This work presents a high‐resolution spatiotemporal analysis of the urban heat island (UHI) effect in Swiss cities during last 6 years. The entire alpine country is simulated at once using COSMO model 1.1 km resolution, validated against dense national measurement network. Additionally, bulk parametrisation TERRA URB used to dynamical and thermal effects areas. resulting data allows us perform first comprehensive over Switzerland, with focus on UHI intra‐urban across comparisons,...
The leading-edge contamination (LEC) problem of an infinite swept wing is shown here as vortex-induced instability. governing equation for receptivity presented LEC in terms disturbance energy based on the Navier–Stokes equation. unperturbed shear layer given by Hiemenz boundary-layer solution two-dimensional and exact incompressible Thus, solved numerically solving full at attachment-line a to convecting vortex moving outside boundary layer, which triggers subcritical spatio-temporal...
Abstract The diurnal cycle is the most prominent mode of rainfall variability in tropics, governed mainly by strong solar heating and land–sea interactions that trigger convection. Over western Maritime Continent, complex orographic coastal effects can also play an important role. Weather climate models often struggle to represent these physical processes, resulting substantial model biases simulations over region. For numerical weather prediction, manifest themselves initial conditions,...