[Bldg-sim] Wind driven rain data
Joe Huang
yjhuang at whiteboxtechnologies.com
Thu Jul 19 11:37:43 PDT 2018
BLDG-SIM had said this post was too large, so I'm resending it with the
picture size reduced.
On 7/19/2018 10:50 AM, Joe Huang via Bldg-sim wrote:
>
> Roel,
>
> I have the following concerns about the approach you seem to be taking
> to define terrain-parameters for wind-driven rain:
>
> (1) you are still basing your investigation on a rather simplistic
> model to derive wind-driven rain from the reported rain fall and wind
> speed, i.e., do you know how reliable is that model?
>
> (2) for these types of correlations, you might want to use wind speeds
> at a much finer time resolution, since what's reported at the standard
> weather stations are random snapshots at an hourly or half-hourly time
> step. You could consider using data from Personal Weather Stations
> (PWS), that are typically at the 5 minute interval and many also have
> an additional channel for gusts. Such weather data, i.e., 5-minute
> data in urban or suburban areas, are currently available for tens of
> thousands of PWS, especially in North America and the UK, on web sites
> such as Weather Underground (www.wunderground.com). One caveat would
> be to know the placement of the PWS, which tend to be on rooftops (the
> problem is worse for official weather stations that are supposed to be
> at 10 m above the ground). If you're interested in the WU weather
> data, let me know via e-mail.
>
> I would not recommend using New York Central Park, or at least you
> should compare the results to that from some other place that's less
> atypical. The Central Park weather station is located at the
> Belvedere (see attached map), which is an isolated building in the
> middle of a large urban park that is in turn surrounded by tall
> buildings and adjacent to some of the tallest buildings in the world.
>
> Yes, I'm aware that the terminal velocity of raindrops varies with
> their size. However, I ignored that factor because any error due to
> using a constant value would be small compared to all the other
> assumptions of the model and besides, I don't think raindrop size is
> recorded in any weather data.
>
> Joe
>
> On 7/19/2018 7:30 AM, Roel Tersteeg wrote:
>>
>> Dear Joe, Julien,
>>
>> Thank you for the extensive replies and your suggestions.
>>
>> The rainfall above an area is not very different between airfield and
>> urban areas, but due to the buildings and trees that may shelter
>> locations in build-up areas this can cause lower rainfall in those
>> locations. As you mentioned the wind will be altered in a more
>> significant way. One thing I would like to do is actually (re)define
>> ‘terrain parameters’ for wind driven rain. A single number, such as
>> in your example, hides the actual uncertainty behind that number. And
>> for that I would like to find measured data, the location of which
>> doesn’t matter that much.
>>
>> The usage of weather stations for the purpose I am looking for is
>> usually not an option as the location of weather stations is such
>> that buildings and trees around the site don’t have an effect on the
>> measurements (typically > 100 m around the site free of
>> obstructions). For the model I am trying to build, the (uncertainty
>> in the) effect of trees and buildings on rain and wind is exactly
>> what I try to model. If you know of weather stations on such sites, I
>> would be grateful if you could help me with that. I will also have a
>> look at the weather stations in central park and see if they can help me.
>>
>> As for the calculation presented, there are several methods (e.g.
>> ISO15927, ASHRAE standard 55) and they mostly have the form of
>> Rainfall*Wind_speed*cos(Wind_direction-Wall_normal), with possibly
>> some factors. There is a bit more explanation in Climatological note
>> 3 from Met Eireann, from which note 13 is an update, how they
>> calculated the map.
>>
>> As a site-note: the velocity of raindrops is dependent on the size of
>> the droplet with larger drops having a higher speed (terminal
>> velocity) that smaller ones.
>>
>> Roel Tersteeg MSc
>>
>> PhD-student
>>
>> Building Energy Research Group
>>
>> School of Architecture, Building and Civil Engineering
>>
>> Loughborough University
>>
>> T: +44 77 56 10 90 54
>>
>> E: R.M.Tersteeg at lboro.ac.uk <mailto:R.M.Tersteeg at lboro.ac.uk>
>>
>> *From:*Julien Marrec <julien.marrec at gmail.com>
>> *Sent:* 19 July 2018 13:26
>> *To:* Joe Huang <yjhuang at whiteboxtechnologies.com>
>> *Cc:* Roel Tersteeg <R.M.Tersteeg at lboro.ac.uk>; Luis Miguel Blanes
>> Restoy <lmblanes at gmail.com>; bldg-sim at lists.onebuilding.org
>> *Subject:* Re: [Bldg-sim] Wind driven rain data
>>
>> Hello,
>>
>> FYI, I can think of at least one location where you'd find probably
>> good quality weather data in a *_big _urban center and not at an
>> airport: Central Park, New York City, USA*, though it's in a quite
>> large park but there are tall buildings all around it, see map
>> <https://www.google.com/maps/place/40%C2%B046%2744.4%22N+73%C2%B058%2708.4%22W/@40.7787947,-73.9765413,15.5z/data=%214m5%213m4%211s0x0:0x0%218m2%213d40.779%214d-73.969>.
>>
>> Note that in NOAA there's a weird thing going on where you have 4
>> stations with different operating dates, one did 1943 to 2010,
>> another 2010 to 2012 or so, and another started after that (I know I
>> said there are four: one did 17 days in august 2010 but overlapped
>> another running one). Here are the USAF-WBAN codes for the two most
>> interesting:
>>
>> 725053-94728 #CENTRAL PARK (2012 to today)
>>
>> 725060-94728 #NEW YORK CENTRAL PARK (2010 to 2012)
>>
>> This data is free and can be accessed at NOAA's ISD (see here
>> <https://www.ncdc.noaa.gov/isd/data-access>)
>>
>> I looked at France's stations in the NOAA database too, since I have
>> a better clue of where things actually are, and it seems that there
>> are a bunch that aren't at an airport, but there are all in seaside
>> towns, so that is probably not what you're looking for...
>>
>> Here are some stations you'll perhaps want to look at, I'm including
>> the three airports around central park too if you want to compare the
>> data. Don't mind the fact that the 'END" date is last year, I just
>> haven't refreshed this file since September 2017
>>
>> USAF
>>
>>
>>
>> WBAN
>>
>>
>>
>> STATION NAME
>>
>>
>>
>> CTRY
>>
>>
>>
>> STATE
>>
>>
>>
>> ICAO
>>
>>
>>
>> LAT
>>
>>
>>
>> LON
>>
>>
>>
>> ELEV(M)
>>
>>
>>
>> BEGIN
>>
>>
>>
>> END
>>
>>
>>
>> KEEP
>>
>> 70020
>>
>>
>>
>> 99999
>>
>>
>>
>> BOULOGNE
>>
>>
>>
>> FR
>>
>>
>>
>>
>>
>> 50.733
>>
>>
>>
>> 1.6
>>
>>
>>
>> 74
>>
>>
>>
>> 19730101
>>
>>
>>
>> 20170902
>>
>>
>>
>> YES
>>
>> 72000
>>
>>
>>
>> 99999
>>
>>
>>
>> PENMARCH
>>
>>
>>
>> FR
>>
>>
>>
>>
>>
>> 47.8
>>
>>
>>
>> -4.367
>>
>>
>>
>> 19
>>
>>
>>
>> 19360102
>>
>>
>>
>> 20170902
>>
>>
>>
>> YES
>>
>> 73150
>>
>>
>>
>> 99999
>>
>>
>>
>> LA ROCHELLE
>>
>>
>>
>> FR
>>
>>
>>
>>
>>
>> 46.15
>>
>>
>>
>> -1.15
>>
>>
>>
>> 10
>>
>>
>>
>> 19290801
>>
>>
>>
>> 20170902
>>
>>
>>
>> YES
>>
>> 76410
>>
>>
>>
>> 99999
>>
>>
>>
>> SETE
>>
>>
>>
>> FR
>>
>>
>>
>>
>>
>> 43.4
>>
>>
>>
>> 3.7
>>
>>
>>
>> 81
>>
>>
>>
>> 19360615
>>
>>
>>
>> 20170902
>>
>>
>>
>> YES
>>
>> 76950
>>
>>
>>
>> 99999
>>
>>
>>
>> CAP FERRAT
>>
>>
>>
>> FR
>>
>>
>>
>>
>>
>> 43.683
>>
>>
>>
>> 7.333
>>
>>
>>
>> 144
>>
>>
>>
>> 19730101
>>
>>
>>
>> 20100412
>>
>>
>>
>> YES
>>
>> 725030
>>
>>
>>
>> 14732
>>
>>
>>
>> LA GUARDIA AIRPORT
>>
>>
>>
>> US
>>
>>
>>
>> NY
>>
>>
>>
>> KLGA
>>
>>
>>
>> 40.779
>>
>>
>>
>> -73.88
>>
>>
>>
>> 3.4
>>
>>
>>
>> 19730101
>>
>>
>>
>> 20170904
>>
>>
>>
>> YES
>>
>> 725033
>>
>>
>>
>> 94728
>>
>>
>>
>> NYC CENTRAL PARK
>>
>>
>>
>> US
>>
>>
>>
>> NY
>>
>>
>>
>> KNYC
>>
>>
>>
>> 40.779
>>
>>
>>
>> -73.969
>>
>>
>>
>> 47.5
>>
>>
>>
>> 19431201
>>
>>
>>
>> 20100731
>>
>>
>>
>> YES
>>
>> 725033
>>
>>
>>
>> 99999
>>
>>
>>
>> NEW YORK CITY CENTRAL PARK
>>
>>
>>
>> US
>>
>>
>>
>> NY
>>
>>
>>
>>
>> 40.767
>>
>>
>>
>> -73.983
>>
>>
>>
>> 27
>>
>>
>>
>> 20100801
>>
>>
>>
>> 20100817
>>
>>
>>
>> YES
>>
>> 725053
>>
>>
>>
>> 94728
>>
>>
>>
>> *CENTRAL PARK*
>>
>>
>>
>> US
>>
>>
>>
>> NY
>>
>>
>>
>> KNYC
>>
>>
>>
>> 40.779
>>
>>
>>
>> -73.969
>>
>>
>>
>> 42.7
>>
>>
>>
>> 20120801
>>
>>
>>
>> 20170904
>>
>>
>>
>> YES
>>
>> 725060
>>
>>
>>
>> 94728
>>
>>
>>
>> *NEW YORK CENTRAL PARK*
>>
>>
>>
>> US
>>
>>
>>
>> NY
>>
>>
>>
>> KNYC
>>
>>
>>
>> 40.779
>>
>>
>>
>> -73.969
>>
>>
>>
>> 47.5
>>
>>
>>
>> 20100801
>>
>>
>>
>> 20120801
>>
>>
>>
>> YES
>>
>> 744860
>>
>>
>>
>> 94789
>>
>>
>>
>> JOHN F KENNEDY INTERNATIONAL AIRPORT
>>
>>
>>
>> US
>>
>>
>>
>> NY
>>
>>
>>
>> KJFK
>>
>>
>>
>> 40.639
>>
>>
>>
>> -73.762
>>
>>
>>
>> 3.4
>>
>>
>>
>> 19730101
>>
>>
>>
>> 20170904
>>
>>
>>
>> YES
>>
>> Best,
>>
>> Julien
>>
>>
>> --
>> Julien Marrec, EBCP, BPI MFBA
>> Owner at EffiBEM <http://www.effibem.com>
>> T: +33 6 95 14 42 13
>>
>> LinkedIn (en <https://www.linkedin.com/in/julienmarrec>) /| /(fr
>> <https://fr.linkedin.com/in/julienmarrec/fr>) :
>>
>> 2018-07-19 3:55 GMT+02:00 Joe Huang via Bldg-sim
>> <bldg-sim at lists.onebuilding.org <mailto:bldg-sim at lists.onebuilding.org>>:
>>
>> Roel,
>>
>> I'm not an expert in this field of liquid precipitation, but here
>> are my thoughts in response to your comments:
>>
>> 1) I'm not aware of drastic differences in rainfall between the
>> airport and more urban areas of a city. However, there are
>> noticeable differences in wind speeds for which, in the absence
>> of measured data, are accounted for in building energy modeling
>> by TERRAIN-PARAMETERs dependent on the general site description,
>> e.g., 1.00 for flat terrain such as an airport, 0.85 for rural,
>> 0.67 for urban or forest, and 0.47 for urban centers with tall
>> building, and the height difference between the measured data and
>> the site. if you're having difficulty in finding either measured
>> wind speed or driving rain data (good luck!), I would suggest you
>> just use the airport data and adjust that with a Terrain Parameter.
>>
>> 2) If you insist on getting rain and wind speed data for a
>> suburban location, I'm sure those can be found among the 8,000+
>> weather stations for which I have hourly weather data, but the
>> locations would be anywhere in the world. Do you care where is
>> the location?
>>
>> 3) The Met Eirerann paper describes a driving rain index, but
>> does not provide the equation. In thinking about it again (note
>> that I've only thought about this after reading your original
>> query), I think a plausible approach would be:
>>
>> a. find the approximate downward velocity of falling rain (a
>> quick web search for "How fast do raindrops fall" gave the answer
>> of 10 m/sec)
>>
>> b. divide that by the (adjusted) wind speed to get the
>> fraction that would fall on a vertical surface, i.e., driving rain.
>>
>> c. multiply the "driving rain fraction" by the reported rain
>> fall to get the amount of driving rain.
>>
>> c. use the wind direction to apportion the driving rain by the
>> wall orientation.
>>
>> It's still not clear to me what is the primary motivation for
>> your investigation. Is it to determine the amount of driving
>> rain at a particular location or weather file? to validate the
>> method to calculate driving rain? Or to just get a handle on how
>> much driving rain is there ?
>>
>> Joe
>>
>> Joe Huang
>>
>> White Box Technologies, Inc.
>>
>> 346 Rheem Blvd., Suite 205A
>>
>> Moraga CA 94556
>>
>> yjhuang at whiteboxtechnologies.com
>> <mailto:yjhuang at whiteboxtechnologies.com>
>>
>> http://weather.whiteboxtechnologies.com for simulation-ready weather data
>>
>> (o) (925)388-0265
>>
>> (c) (510)928-2683
>>
>> "building energy simulations at your fingertips"
>>
>> On 7/18/2018 5:43 AM, Roel Tersteeg wrote:
>>
>> Dear Joe and Luis,
>>
>> Thank you for your replies to my question and apologies for
>> my very late reply to you both. Unfortunately the data from
>> official, synoptic weather stations is airfield data and thus
>> not applicable to my situation as there is no difference in
>> microclimate (no changes in wind or rainfall due to
>> surrounding building). The same goes for the Met Eireann
>> information (if of interest, the Climatological notes 13 and
>> 3 about wind driven rain can also be found and downloaded
>> here as well:
>> https://www.met.ie/education/publications/climatological-notes)
>>
>> I am looking specific for wind driven rain data, or indeed
>> combined wind and precipitation data that can be converted to
>> wind driven rain, for different (sub)urban settings. The
>> suggestion for looking at ‘personal weather stations’ is very
>> interesting, although this has the issue of uncertainty about
>> the quality of the measurements.
>>
>> Kind regards,
>>
>> Roel
>>
>> *From:*Luis Miguel Blanes Restoy <lmblanes at gmail.com>
>> <mailto:lmblanes at gmail.com>
>> *Sent:* 06 July 2018 14:34
>> *To:* Joe Huang <yjhuang at whiteboxtechnologies.com>
>> <mailto:yjhuang at whiteboxtechnologies.com>
>> *Cc:* bldg-sim at lists.onebuilding.org
>> <mailto:bldg-sim at lists.onebuilding.org>
>> *Subject:* Re: [Bldg-sim] Wind driven rain data
>>
>> Joe
>>
>> Try this link
>>
>> https://es.scribd.com/document/346851908/MET-Driving-Rain-Index-IRELAND#close_user_settings_menu
>>
>> Regards
>>
>> Luis
>>
>> On Thu 5 Jul 2018, 04:28 Joe Huang,
>> <yjhuang at whiteboxtechnologies.com
>> <mailto:yjhuang at whiteboxtechnologies.com>> wrote:
>>
>> Luis,
>>
>> Thanks for the tip. I went to the link, which by the way
>> is for the Irish Meteorological Service, and read that
>> it said, "The amount of rain received by a wall
>> correlates fairly well with the product of rainfall and
>> the component of the wind speed normal to the wall. This
>> led Lacy and Shellard to propose the product of the mean
>> annual rainfall and the mean annual wind speed as a
>> driving rain index which is proportional to the total
>> rainfall driven in one year on to a vertical surface
>> always facing the wind", which is functionally quite
>> close to what I was envisioning, i.e., WDR = LP * f(wspd,
>> wdir), where LP is Liquid Precipitation or Rainfall.
>> However, when I clicked on the link to the actual paper
>> cited, the Meteireann web site responded that "404:
>> Page not found". Therefore, I still don't know the
>> function that converts LP or rainfall to WDR.
>>
>> Joe
>>
>> Joe Huang
>>
>> White Box Technologies, Inc.
>>
>> 346 Rheem Blvd., Suite 205A
>>
>> Moraga CA 94556
>>
>> yjhuang at whiteboxtechnologies.com
>> <mailto:yjhuang at whiteboxtechnologies.com>
>>
>> http://weather.whiteboxtechnologies.com for simulation-ready weather data
>>
>> (o) (925)388-0265
>>
>> (c) (510)928-2683
>>
>> "building energy simulations at your fingertips"
>>
>> On 7/4/2018 2:30 PM, Luis Miguel Blanes Restoy wrote:
>>
>> Hi Roel and Joe
>>
>> Did you look at available data from Met Eireann?
>> There is a paper regarding WDR index calculation
>> method that may be of your interest. See below link.
>>
>> https://www.met.ie/climate/what-we-measure/rainfall#
>> <https://www.met.ie/climate/what-we-measure/rainfall>
>>
>> Regards
>>
>> Luis
>>
>> On Wed 4 Jul 2018, 22:12 Joe Huang via Bldg-sim,
>> <bldg-sim at lists.onebuilding.org
>> <mailto:bldg-sim at lists.onebuilding.org>> wrote:
>>
>> What is your definition for Wind-driven Rain?
>> Practically all weather station reports,
>> including official stations available in NOAA's
>> ISD as well as unofficial "Personal Weather
>> Stations" hosted on WeatherUnderground, contain
>> information on liquid precipitation (LP), wind
>> speed, and wind direction. Can the WDR be
>> calculated from these standard parameters, maybe
>> as the LP * f(wspd, wdir) ?
>>
>> Joe
>>
>> On 7/4/2018 3:52 AM, Roel Tersteeg via Bldg-sim
>> wrote:
>>
>> Dear all,
>>
>> For the verification of a model to estimate
>> wind driven rain (WDR) I would like to use
>> WDR data from different microclimates (rural,
>> (sub)urban). I have access to several data
>> sets of free field or airfield WDR
>> measurements from different locations and the
>> results from a measurement campaign in
>> Vancouver. To better evaluate the model I
>> would like to use measured data from one or
>> more locations with different microclimates,
>> not being free field or airfield sites.
>>
>> My question is if someone knows if
>> measurements are available of wind driven
>> rain in one or more microclimates?
>>
>> Kind regards,
>>
>> Roel Tersteeg MSc
>>
>> PhD-student
>>
>> Building Energy Research Group
>>
>> School of Architecture, Building and Civil
>> Engineering
>>
>> Loughborough University
>>
>> T: +44 77 56 10 90 54
>>
>> E: R.M.Tersteeg at lboro.ac.uk
>> <mailto:R.M.Tersteeg at lboro.ac.uk>
>>
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