https://analytics.envi-met.com/hg2e/ 2026-04-12T18:56:58+00:00 https://analytics.envi-met.com/hg2e/ https://analytics.envi-met.com/hg2e/lib/tpl/envimet/images/favicon.ico text/html 2017-11-10T09:25:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:compute&rev=1510302349&do=diff Running ENVI-met The user friendly interface of ENVI-met sometimes makes people forget that they work with a sophisticated climate simulation system. Normally, these kind of numerical models can only be run on complex and extremely expensive supercomputers. In more than 20 years of ENVI-met developement, we have invented various technologies to bring the scientific power of physical climate simulation models to your desktop. ENVI-met uses a complex system of optimized algorithms and intelligent… text/html 2022-10-03T18:06:46+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:faq&rev=1664813206&do=diff FAQ ENVI-met This page lists some of the most frequently asked questions about ENVI-met. If you do have questions about ENVI-met, first look at our Forum/ Bulletin Board! Maybe your question has been anserwed before...If NOT,.... make a new post in the forum!!!! Basic Questions text/html 2017-11-10T09:25:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:flow&rev=1510302349&do=diff Flow Problems Flow Problems: Reason and Handling With no doubt, flow problems are the number one troublemaker in simulations (at least since the turbulence model got the smart trouble shooting implemented). Flow problems are indicated by the ENVI-met message text/html 2017-11-10T09:25:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:instable&rev=1510302350&do=diff Instability/ Numerical Errors The problem... In complex Model Areas (and sometimes even in configurations you consider as being “simple”) you might experience numerical instabilities from time to time. These instabilities appear as “PANIC Dumps text/html 2025-02-18T14:51:41+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:ivs&rev=1739886701&do=diff Integrated View Sphere (IVS) vs. Averaged View Factor (AVF) Secondary radiation in ENVI-met Accurate simulation of radiative transfer is a very important aspect in climate modeling. For microclimate models in particular, it is not only important to simulate primary but also secondary radiative fluxes in great detail, i.e. emitted longwave and reflected shortwave radiation. As there are always limitations regarding computational effort and memory, these radiative fluxes are commonly implemented… text/html 2017-11-10T09:25:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:lad&rev=1510302350&do=diff Obtaining Leaf Area Density Data [Leafs on a tree] The Leaf Area Density (LAD) is the portion of leaf surface ($m^2$) within a volume of air ($m^3$). The formal unit is $$ \frac{ \text{Leaf surface } (m^2)}{ \text {Reference volume } (m^3)} $$ In ENVI-met, like in most other models, the LAD is counted one-sided which means that only one side of the leaf is counted as active surface area. This accounts to the fact, that most plants only have $LE$$H$$LAD$ text/html 2017-11-10T09:25:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:lbc&rev=1510302350&do=diff Lateral Boundary Conditions Lateral boundary conditions define the way, the model behaves at its lateral boundaries. This is a very specific setting and you normally do not need to change these settings. From Version 4 on, it is recomended to use at least the $K_m$$K_m$$K_m$$K_m$$K_m$$K_m$$K_m$$$ K_m(z)= \kappa \cdot z$$$\kappa$$z$ text/html 2017-11-10T09:25:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:lwflux&rev=1510302350&do=diff Longwave Flux Divergence Objective In ENVI-met versions below V3.1, the effect of longwave flux divergence was taken into account only for the ground and leaf surfaces, but not for the free air itself. As the longwave fluxes inside urban environments are very complex and not only driven by vertical fluxes but also by horizontal fluxes, it was considered to be too complex to be included in the model. text/html 2017-11-10T09:25:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:modelheight&rev=1510302350&do=diff Total Model Height What is the Minimum Model Height? Selecting the correct size of the model domain is a central aspect in successful numerical modelling. Whereas the horizontal dimension is more or less given by the dimension of your subject of interest, the vertical height of the model is less obvious and can - if not selected properly - cause major problems. text/html 2017-11-10T09:25:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:modellayout&rev=1510302350&do=diff Knowledge Base: Model Layout [Schematic Overview of the ENVI-met Model Layout] Basic Layout of ENVI-met Obviously, it is not possible to describe the complete model design in a few paragraphs. The sketch above aims to give you an impression over the very basic structure of a microclimate model like ENVI-met. text/html 2018-07-29T20:59:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:nesting&rev=1532890776&do=diff Nesting Grids Why do I need Nesting Grids? Practically you don't need them. You can restrict your simulation to the main (core) area without adding any grids as nesting area. In times of large computation power, we recommend to not use Nesting Grids anymore but to include more grid cells at the borders within the $$ \Delta xy (n)= \Delta xy(Main) *n $$$\Delta xy(Main)$$n$ text/html 2021-04-21T09:38:57+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:parallel&rev=1618990737&do=diff Parallel Computing in ENVI-met Starting with Version 4.3, ENVI-met allows parallel computing on several CPU cores in the full versions (BUSINESS/SCIENCE). The BASIC and STUDENT editions do not support parallel computing. Parallel computing is a wonderful option to reach never observed calculation speeds, but it is also a source of pitfalls and misunderstandings. According to Stephen Toub from Microsoft [1], there are even pitfalls for pitfalls. text/html 2018-07-29T21:18:20+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:receptors&rev=1532891900&do=diff Creating Time Series using Receptors Purpose of Receptors The standard output files provide data covering the complete model domain in two or three dimensions. Each time, the model saves its state, a new output file is created. These files are handy for analyses of the spatial distribution of the different variables, but on the other hand, there are many thinkable situations, where the user is interested in the temporal development (time series) of variables at certain points inside the Mode… text/html 2021-07-26T21:07:45+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:review&rev=1627326465&do=diff Evaluations & Reviews Introduction A system like ENVI-met generates a huge amount of different data about many different aspects of the environmental system observed. It is impossible to assess and evaluate all these data in one. Moreover, a model is a model and the reality is the reality. There is a conceptual difference between both systems, hence a complex program cannot be text/html 2017-11-10T09:25:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:rotation&rev=1510302350&do=diff Model Rotation Using Model Rotation It can be handy to use a different model orientation than the default one (Y-axis pointing to North). For example if a street canyon is analysed that has a different orientation, it is not clever to turn the buildings lining the street into text/html 2021-11-11T12:30:20+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:sources&rev=1636630220&do=diff Pollutant sources in ENVI-met The simulation the dispersion of passive and active pollutants is one of the most complex tasks when using ENVI-met. The calculation of the transport and deposition of pollutants requires everything a full microclimate simulation needs to be run successfully plus additional information concerning the pollutant emissions. This Knowledgebase should help you to find your way in this process. text/html 2021-11-11T19:53:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:start&rev=1636656828&do=diff ENVI-met Knowledgebase Overview The ENVI-met Knowledge Base aims to explain some of the ENVI-met features and aspects about the simulation in deeper detail than the basic documentation does. It also is an essence of the different FAQ and disussions raised in the ENVI-met bulletin board over the time. text/html 2017-11-10T09:25:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:topbar&rev=1510302350&do=diff  * →Home * →Knowledgebase * FAQ's * Model Layout * Model DataFlow * Vertical Grid Layout * Nesting Grids * Total Model Height * Lateral Boundary Conditions * Model Roatation * Using Receptors * Sources in ENVI-met * Flow Problems * Turbulence Model * Wall Temperatures * Instability/Numerical Errors * Longwave Flux Divergence * Obtaining Leaf Area Density Data * eDocuments * my eBook text/html 2022-04-04T19:26:03+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:turbulence&rev=1649093163&do=diff Turbulence Model Turbulence Model in ENVI-met ---- this information is outdated --- ENVI-met uses the so-called 2-equation Turbulence Kinetic Energy (TKE) Model to predict the turbulence in the air. The first equation describes the distribution of the kinetic energy (E) in the air depending on production, advection, diffusion and destruction: text/html 2021-03-19T10:17:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:verticalgrid&rev=1616145420&do=diff Vertical Grid Layout Different to the horizontal grid, the vertical gridding is not too obvious but still as important as the horizontal grid setup. In Concept Design models (2.5D), the vertical grid is generated on-the-fly based on the model settings such as building heights. You can change the settings for the vertical grid setup at any time. In $\Delta z$$k$$$ \Delta z(k) = \left[ \left( 1 \frac{s}{100} \right) \right]^{k-1} \cdot \Delta z_{start} $$$s$$\Delta z_{start}$$z_T$$\Delta z_{st… text/html 2021-07-26T21:05:14+00:00 Anonymous (anonymous@undisclosed.example.com) https://analytics.envi-met.com/hg2e/doku.php?id=kb:walls&rev=1627326314&do=diff Wall Temperatures FIXME While the general concept is correct, wall temperatures are no longer stored in the normal 3D files in post V4. Needs rework Storage of Wall Temperatures As each grid cell can include up to 6 walls, the storage of the wall temperatures has to be different from the other variables, where only one value per grid is stored.