Best posts made by Korina

Reading the latest news, everybody has to be concerned about the Coronavirus and its impact on daily life of billions of people. The Coronavirus (virus is officially labeled as SARS-CoV-2 and its disease as COVID-19) is spreading quickly around the world, causing unprecedented lockdowns of huge regions and cities, havoc on markets and overload of health facilities in affected areas.

Some countries seem to have already contained the major spread of virus (China, South Korea), some are currently experiencing the initial extreme increase of patients with severe cases (Italy, Iran), with the rest of the world expecting it in upcoming weeks and trying to prepare for it.

Question is, will the rate of spread slow down or even disappear at all? It definitely will.

Check this nice video demonstrating the principle of exponential growth and epidemics

It’s essential to understand that even a very small decrease in “probability of exposure becoming an infection” (referred as p in the video) can reduce the growth of the spread significantly or even stop it completely.

But why do we discuss it at Windy.com, we normally talk just weather, right?

The reason is the outside temperature. Spread of typical flu highly correlates with weather, having its season peak in cold months, declining during spring with almost no cases during the warmest part of the year. Recent studies show that high temperatures and especially high humidity slows the influenza spread. More moisture in warmer air behaves as a barrier for airborne viruses so droplets of cough or sneeze cannot travel as far as they would in colder, dry air.
Of course, more factors can play a role in this flu seasonality (longer sunlight exposure, less clustering of people indoors), but temperature is considered as the major one.

There is a whole family of coronaviruses, some of them already known to humans, causing mild colds and behaving similar to the flu - in warmer climate, they tend to decline. That is the reason why many people believe that same will happen with COVID-19. As stated above, even the slight decrease in person to person transfer rate of the virus has a huge impact on overall number of cases. Will a higher temperature and humidity help us in this way? There are many opinions on that subject, but most experts agree, that it’s too early to judge and only hard data from summer season and their detailed analysis will tell us the truth.

But until then, we have no other option than to make assumptions based on data we have now.

Posts discussing weather patterns (temperature/humidity):

Also check out:
Coronavirus outbreakt

The perspective

As mentioned, the COVID-19 is not all that unknown to us, we had coronavirus strain SARS back in 2003. SARS had its peak in winter months and faded away during May. Typically influenza season falls sometimes between the beginning of fall and the end of spring. So the SARS did not really exceed the usual influenza season trend. But can we expect COVID-19 to follow this path as well?

The current spreading rate tells us a fact, that the COVID-19 has more incidences in places with dryer and colder environment than in more humid and warm locations. For instance let´s take a look at Japan, we would expect the virus to be spreading mainly in big cities like Tokyo, due to a number of foreign visitors and population. But this is not the case, COVID-19 is actually spreading in Hokkaido, despite it has a much lower frequency of travellers. However the weather conditions there are favorable, dry and less humid environment. The same goes for Italy and its epicenter Milan. North of the country is significantly more affected than the south.

On the other hand, it would not be wise to expect the novel coronavirus to behave as the ones before.
It is necessary to say, that SARS 2003 did not go away just because weather got warmer. It was followed by national interventions to isolate cases and everyone, who had the possibility to be infected.

We have already said that the environment plays a key role in influenza activity and dry/cold weather with low humidity favors the transmission. But influenza epidemics often appears in a tropical and subtropical regions during rainy seasons with obviously high humidity values. In other words, there are two types of influenza environments. In cold-dry environment, where humidity/temperature goes below 11–12 g/kg and 18–21°C, influenza peaks during cold months. In humid-rainy case, if humidity/temperature does not go under those values, influenza peaks during rainy season.

Immunity is another factor, which is worth a consideration. Our immunity is significantly worse in winter than in summer and we also lack vitamin D, because of less ultraviolet light exposure in cold months. Vitamin D benefits our immune system and helps us to be durable against numerous diseases, even so this factor can be observed as not so important in relation to influenza activity.

But then again, new viruses are likely to persist longer than a common ones, which have been in the population for years or decades.

Available data

We at Windy.com are no experts in the area of viruses, but we have access to the best weather data available.

We have assembled temperature records for each country (taken from the area of major spread of the virus within the country or the capital of that country) and pictured them along with recent Coronavirus spread data (daily amount of new cases, sourced from Coronavirus COVID-19 Global Cases by Johns Hopkins CSSE) to see if there could be any correlation.

Based on the charts above, we can see a slight correlation in relation with a higher temperature and virus decrease, and opposite a lower temperature and faster spread of COVID-19.

Of course, there are many drawbacks in this approach:

• data coming from different countries aren’t easily comparable (some countries test much more than the others, some have much highly populated areas, also quality of data coming from some countries is more than questionable)

• the virus has quite a long incubation period, therefore “new” cases are being reported several days after the people were actually infected (but at least average temperature at given location can help to mitigate this effect)

• there are still not that many daily observations, the data window is quite too small

• correlation does not imply causation” - even if there seems to be a visual dependency between the temperature and the increase/decrease rate of new cases, it is absolutely no proof that there is a correlation between those two

As always there are many opinions and very little data to predict anything for sure. So the truth will be somewhere in the middle. It should be essential to avoid any catastrophic predictions as well as not to underestimate it.

The latest data for China shows a retreat of Coronavirus cases and high amount of recovered patients in a comparison to the total amount. Other countries will hopefully have the same progress.

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Not happy with the findings? Don’t despair. If the weather won’t help us, there are still many ways, how each of us can help - avoid crowded places, work remotely if possible, stay fit, wash your hands, do not touch your face.
Avoid face to face social contacts for a while - read a couple of books or go online! There is still a lot to explore, also at Windy.com.

And it truly was.. Windy team once again went on an adventure, and this time we decided to conquer Norway and its snowy hills covered with picturesque cottages.

Our journey started on Prague’s airport, where we had a flight to Oslo and from there we took a long ride by car (5,5 hours) until we arrived in Ustaoset, Buskerud, where we stayed for a week on our colleague’s cottage. (Many thanks again to Honza for the invitation and the hospitality!).

There was really no shortage of snow. Ustaoset is 990m above the sea level and is the finish spot for the cross country ski event Skarverennet. So the scenery was great and view from cottage’s living room, even better.

Due to coming storm Dennis the weather was not ideal especially in the beginning of our week. So the first day we spent working and making plans for the upcoming days.

When the weather got better, there was a plenty of options what we could do!

Kiting

Probably the most tempting activity we all wanted to try was snowkiting.
Since most of us are complete beginners, we had our instructors nearby to teach us the basic techniques to operate the kite and help us.

Kiting is certainly not one of the easiest sports you can do, in the beginning, you spend quite a bit of time untangling your kite, because it tends to get out of control a lot and you have to put it in the air over and over again.
It frankly requires a bit of patience, but once you get into it, you will love it.

It was a great feeling to chase winds on a snowy plains either on skies or snowboard.

A little different camping

Since we saw a chance to get the true nordic night experience firsthand, we took the challenge and a few of us decided to spend a night outside.

We did have all the necessary equipment and experienced instructor to guide us through. So the fun could begin!

We had to start building two tents early in the afternoon to get things done in time.
KP for aurora borealis was 4 at that time, so there was a little chance, but we still secretly hoped to catch it.
A few hours later, the two tents were standing, tops of mountains started to get a pink tint and we were about to call it a day, cooked dinner and went to a bed early.

Nevertheless, since we know how to command weather, we did see aurora borealis in the end.
In the morning, still in a shadow of the past night, green as an emerald, just as we all pictured it. :)

Skiing and the surprise

Norway has quite a few skiing resorts and the one we went to was Geilo. It happens to be the 5th best resort in Norway, located just a few kilometres from Ustaoset. The first impression was half empty slopes with a fresh powder snow, so actually really nice.

After we enjoyed a full day of sunny weather in the mountains, we joined an evening surprise, which was a night sledding and a hot bath outside for the more venturesome among us.

Here is a little sneak peek on how we pulled it off in the end:

Amid the COVID-19 measurements, Copernicus monitors a 10% per week reduction in NO2 surface concentrations since mid-February.

While the question of improved air quality is a secondary concern with the world facing the COVID-19 crisis, satellite observations detected abrupt changes in activity levels in Northern Italy, where dense surface observation of the pollutant nitrogen dioxide (NO2) shows a gradual reduction trend of about 10% per week over the last four to five weeks.

The Copernicus Atmosphere Monitoring Service (CAMS), implemented by the European Centre for Medium-Range Weather Forecasts on behalf of the European Commission, provides daily analyses of hourly concentrations of regulatory air pollutants, which can serve as “ground truth” to assess quantitatively and in more details the changes in concentrations identified from satellites and attributed to the effects of COVID-19 measures across the world.

The CAMS regional air quality analyses come in the form of hourly gridded maps and are obtained by combining satellite observations, surface in situ observations and numerical modelling. Taking the point covering the city of Milano, the hourly timeseries of surface concentration of NO2 since January 1st is shown below.

While no clear trend is visible over the first five weeks of the year, a decreasing trend can be seen starting during week 6 and continuing to date. Average NO2 concentrations were around 65 mg.m-3 in January, 45 mg.m-3 in February, and around 35 mg.m-3 for the first half of March. The linear decreasing trend on the daily average since week 6 is of the order of -4 mg.m-3 per week. Similar decreasing trends are found for other cities in Northern Italy, such as Torino or Bergamo. In the East, there seems to be rather a step change: in Bologna, concentrations were on average around 30 mg.m-3 in January and are on average around 15 mg.m-3 since the beginning of February (35 mg.m-3 and 15 mg.m-3 for Venezia).

“What the satellite observes is proportional to the vertically integrated amount of pollutants from the ground up to the top of the atmosphere”, explains Vincent-Henri Peuch, Director of Copernicus Atmosphere Monitoring Service. “This is quite different from the concentrations at the surface and even more so from the emissions. Given these limitations, it is quite remarkable that a signal of decreasing activity levels could be detected. This shows the extent of the measures taken by Italy.”

NO2 is a short-lived pollutant. Once emitted, it will stay in the atmosphere generally less than a day before being deposited or reacting with other gases. This means that this pollutant remains fairly close to where it has been emitted. Most of its emissions sources are located at the surface and are generated by human activities such as traffic, energy production, residential heating, industries, etc. The sources vary greatly during the day, as well as depending on the day in the week and the month. It also depends on factors such as weather, as a cold spell will trigger increased residential heating and energy demand.

CAMS is continually monitoring the air quality over Europe and on a global scale, providing the data to most leading websites and smartphone applications such as Windy, The Weather Channel, Breezometer or Plume Labs.

What is CAMS?

CAMS is implemented by ECMWF on behalf of the European Commission.
CAMS regional air quality analyses are operationally produced by a consortium of contractors led by Météo-France and INERIS (France). These partners rely on surface air quality observations provided by the European Environment Agency, which gathers them from each individual country.

The CAMS regional air quality analyses come in the form of hourly gridded maps and are obtained by combining satellite observations, surface in situ observations and numerical modelling that mimic the laws of physics and chemistry in the atmosphere. The data collected is of high quality and can be considered as “ground truth”. The main limitation of this dataset is that it cannot account for fine spatial variability and local effects that occur within a few meters to hundred meters near a source, like a road segment with heavy traffic or a power plant chimney stack. The data is representative of the average background values over a grid with a scale of 10km by 10km. The data can be obtained openly and freely from CAMS’ Atmosphere Data Store.

Can satellites really observe air pollution at the surface?

The European Commission’s Copernicus Sentinel-5 Precursor (S-5P) TROPOMI instrument benefits from an unprecedented spatial resolution of 3.5km x 5km, which allows to see fine maps of a number of air pollutants such as NO2. Satellite observations have however some limitations on the level of detail at which they can be used for monitoring air pollutants.

Firstly, they make their measurements from satellites in Low-Earth-Orbit and provide only one measurement per day for each location on Earth: for example, the overpass time of S-5P is 13:30 Mean Local Solar time. Second, the physics of the atmosphere is such that for pollutants like NO2, measurements are not possible or significantly degraded in the presence of clouds and of fine particles suspended in the air (aerosol). During the winter in Europe, this means that only about 25% of the data can be used.

To overcome this issue, observations can be averaged over longer periods of time (typically a running average of 10 days), in order to have at least one or two measurements for each location in each average period. Finally, and most importantly, what the satellite observes is proportional to the vertically integrated amount of pollutants from the ground and up to 10 km (tropopause); this is obviously different from the concentrations at the surface, let alone the emissions by human activities. Given these limitations, it is striking that a clear signal of decreasing activity levels could be detected. Over Europe, high-quality surface observations are made by each individual country and gathered by the European Environment Agency in Near-Real-Time. These observations can serve as “ground truth” to assess the reality of the signal detected by satellite.

What is the situation in other parts of Europe?

In other parts of Europe, the detection of statistically robust trend is yet more challenging, as shown below for some capitals in North-Western Europe. Weather-related episodes of high (between weeks 3 and 4; week 6) and low NO2 surface concentrations are the main features that can be seen.

What are the plans of Copernicus for monitoring emissions using satellites in the future?

As part of the Copernicus programme, CAMS is currently developing a capacity to derive emissions directly, using further advanced modelling techniques. An essential ingredient for this will be the new generation of satellites monitoring air pollutants. These will be embarked on geostationary platform and will provide hourly observations over selected part of the world.

The Korean Aerospace Research Institute’s Cheollian 2B satellite, which was launched into orbit aboard an Arianespace Ariane 5 rocket on February 18th, hosts the first instrument of this kind, GEMS (Geostationary Environment Monitoring Spectrometer); scientifically useful data covering parts of Asia is expected to be available at the end of this year. Similar instruments are planned over the US (TEMPO) and Europe. As part of Copernicus, the Sentinel-4 instrument onboard Eumetsat’s Meteosat Third Generation will launch in late 2022 or 2023. Sentinel-4 will be the backbone for the planned emissions information service of CAMS, which will be operated by ECMWF.

@Klyen @Snicker666-0 @Snicker666 @Gkikas-LGPZ @PRIIME @Wrecked
Hello, the Norwegian radar has been fixed. Thank you for the reports!

Each model has a different update time and it could be confusing what connection does it have with the update time.

Here is the explanation:

• Reference time - is the time when a model starts a new forecast block.

It consists of:

Initialisation - data are entered into the model, this creates Initial conditions (initialisation time) and then model starts calculating conditions.
Assimilation - normalisation on data and assembling data for computation.
Computation - calculating the future atmospheric rates of change in time increments.
Data extraction - extracting data into regular forecast intervals.
Data storage - data are stored and written in accessible format.
Data postprocessing - special postprocessing routines

For example model ECMWF has an update interval 12 hours, that means the first reference time will be 00:00:00Z (Zulu time) and second one 12:00:00Z.

• Update time is time between the reference time and the actual update.
  The whole process of data computation takes approximately from 8 to 9 hours.

So for ECMWF model the update times are 07:15:00Z and 19:15:00Z.
See the exact update times here - When and how often are the weather data updated?.

Where to find info about reference and update time:

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Windy Webcams is another direction which has emerged from our endeavours of making the world even more accessible for everyone.

Our vision represents delivering access to thousands of webcams all over the globe capturing worlds places and giving you the opportunity to be informed by up-to-date images of a diverse locations. We are eager to connect webcam owners with users on one platform.

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Travel and have the world in the palm of your hand

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Have easy API access to thousands of webcams and be well-informed. Enhance your business with visual and authentic content and choose from the world's biggest inventory.

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Join the community and make your webcam go live for broad user audience with possibilities of an enormous reach.

For more details go to How to add a webcam and submit your application here

To submit your webcam you need to go through our form HERE, which contains a few simple questions.

Once you submit your webcam application, our part in the process comes in and we will review your submission.

If approved, you will be notified about the successful permission and your webcam will go live.

A few things to keep in mind for the submission

• Your webcam server needs to have IP addresses coming from outside on the white list, since we often experience issues with servers blocking our IP addressed by default

• We will test your webcam if downloading data on regular daily basis is possible, therefore it is important to provide us with correct image URL

• We only save images which are publicly available on our website from timelapse slideshows. It is up to the owner of the webcam what time period is selected

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• Submit your webcam

We would like to inform you about a short planned suspension of rapid scan data for Europe provided by one of the Eumetsat satellites until 03.02.2020. The satellite coverage however stays preserved since we substitute the missing data with ones from another satellite.

Thank you for your understanding.

Hi @Meteo-Mezzomonte, I have good news for you, we have decided that full screen and time-lapse features will be implemented into Windy webcams again. So stay tuned.

Hi @windy-7p, you can choose all the models including GFS in the App. Just open side menu and scroll to the bottom where you have the selection of models.

@BrianB-2 Hi, it is not possible to display both at the same time.

@dljonesaz @seeletw
Hello, Windy.com gets the SO2 mass data from NASA model GEOS-5, but we don't display archive data. There is an explanation of data right in the layer.

You can also find more information on NASA's website - https://so2.gsfc.nasa.gov/

Dear @WhiteKite20,

regarding the used verb forecast, both versions of past tense are grammatically correct and widely used in diverse types of writings.

Best regards, Korina

Dear @geglinto,

if you would like to set the temperature to Fahrenheit as a default option, please go to Settings, while you are signed in, and change temperature from Celsius to Fahrenheit. Your settings will save and temperature will be shown in °F in all devices. Hope this helps. Korina

Hi @Sevno, could you please send us more information on - info@windy.com preferably with the no content email you received as well? We will have a look at it.
Once you submit your webcam form, it goes into assessment and it may take 1 - 2 working days.

Delay was resolved, ECMWF is updated.

Hi @onetrev, due to license matters, we are unable to display radar in New Zealand at the moment.

Hello @dibster, thank you for your feedback. Regarding the colors, you can adjust the color scheme in settings -

Dear users,

since many of you experience several problems with the widget, here are a few tips what you can do when you notice some of them.

Widget issues are being reported here - https://community.windy.com/topic/5909/widget-problems. Please continue reporting in this thread, it helps us with the improvements.

When reporting, please state type of phone / OS and its version / Windy version / nature of the widget problem

Tips:

• Have the Power saving mode turned off
  Being on this mode prevents widget from downloading data

• Don't be on Do not disturb mode
  It can also prevents widget from functioning properly

• Have the option Background data usage or Background network usage turned on

• Have Windy.com installed on internal phone storage
  Having it installed on SD card can cause functionality problems and glitches

• Try to reinstall the App and place widget on screen again

• Update to the newest version of Android / iOS

• Update to the newest version of Windy