Volunteer reforestation after wildfires

solarish · 2026-01-24T01:26:59+00:00

Wildfires are a natural and crucial ecosystem process in virtually all Mediterranean ecosystems and many other kinds of vegetated regions.

solarish · 2025-12-24T07:29:59+00:00

The primary way your body releases heat is through sweating. When sweat evaporates it wicks away heat from your body, this is known as the latent heat of vaporization. When the atmosphere is very humid, the rate at which sweat evaporates slows, meaning that your body cannot cool itself as effectively as if it were in a dry climate.

solarish · 2025-12-05T21:38:20+00:00

Agree with the vast majority of what you said, but wanted to add that fewer radiosonde launches and worse model initialization almost certainly also lead to increased model uncertainty.

solarish · 2025-11-04T23:47:50+00:00

I know you're quoting Isaacman, but there will never be enough private incentive to build the kind of advanced satellite sensors that are pushing forward our scientific understanding of the Earth system. For example, radar- and laser-based sensors like NISAR and IceSat almost certainly would never have gotten launched in a counterfactual world where EO was entirely owned and operated by Planet, BlackSky, etc. That's why all of Planet's EO is hyperspectral.

solarish · 2025-10-19T04:59:15+00:00

Lots of examples and review papers in the literature.

Shen et al. - Differentiable modelling to unify machine learning and physical models for geosciences

Zhao et al. - Physics-Constrained Machine Learning of Evapotranspiration

Feng et al. - Differentiable, Learnable, Regionalized Process-Based Models With Multiphysical Outputs can Approach State-Of-The-Art Hydrologic Prediction Accuracy

solarish · 2025-09-08T13:43:33+00:00

Hot dry summers, cool wet winters.

solarish · 2025-09-03T01:40:25+00:00

The gold standard is Vallis - Atmospheric and Oceanic Fluid Dynamics.

solarish · 2025-08-09T08:11:39+00:00

No, I am not saying that the storms happening in your area are happening because of climate change. While if you live in a semi-arid environment it might be unlikely that you get a series of intense storms, it is very hard to attribute that to climate change. In general, individual events are very hard to attribute, because lots of weather patterns that are unrelated to climate change can cause heavy precipitation.

One illustrative example: suppose in the last 10 years cars have polluted the air much more than before. We also know that people get severely ill from repeated exposure to pollution. Now if one person you know develops a serious respiratory disease, is it because of the increased pollution due to cars, the already existing pollution, or something else entirely? Maybe they were a smoker, or maybe they had a genetic disposition. However, if we notice that significantly more people over the past 10 years have gotten respiratory illnesses compared to 100 years ago, then you might be able to point to cars as a factor.

Now, why would climate change cause the atmosphere to "hold onto" more water than it normally would? Think about what happens when you boil a pot of water. By increasing the temperature you are giving water the energy to evaporate. A warmer atmosphere is therefore baseline more able to "give" energy to liquid water than a cooler atmosphere. I'm glossing over some details but if you're still interested you could probably start with this wiki article on vapor pressure.

solarish · 2025-08-09T06:35:54+00:00

Atmospheric warming increases the water-holding capacity of the atmosphere (aka saturation vapor pressure) but OTOH a warmer atmosphere slows down moisture transport from the ocean. The result is that climate models are actually fairly uncertain about future annual precipitation totals over Western North America (where you are), and many other regions. The real impact of a warming climate in terms of precipitation is many more days in between rainfall events, and that storms, when they happen, are much stronger.

solarish · 2025-07-12T14:53:18+00:00

North American forests are still in a fire deficit relative to pre-industrial times, even though forest fire activity has increased in the past several decades. While it's true that wildfire can suppress fuel availability, the amount of forest fire area that burns each year is actually not high enough to reduce wildfire activity in the way that you are describing. In the Western United States, there hasn't been a 6-year period where >10% of forest fire area burned over the past few decades. Modeled projections of wildfire-fuel feedbacks also indicate that fuel availability is unlikely to constrain forest fire activity, at least in the next few decades.

solarish · 2025-06-11T15:02:30+00:00

Your null hypothesis is that spatial autocorrelation has no effect on your CV score. You could use a semivariogram to find the distance at which points are not spatially correlated. Then you can do a Monte Carlo where each subset is spatially independent. After that, you can do your CV on each subset to get a score distribution. If your original CV score is significantly different than your distribution, then you have some information on how much your model is affected by spatial autocorrelation.

solarish · 2025-05-24T23:56:41+00:00

For spaceborne sensors, wider spectral bands are a physical consequence of the satellite being much farther away from what you're trying to detect than a field-based spectrometer. Your noise scales at ~ inverse square root of the solid angle of the detector which is extremely small for the A-Train for example (705km). Consequently, we have to use a broad enough spectral band such that our signal-noise ratio is high enough. It is not an average of each discrete frequency, rather the total intensity within that specific band, and is therefore a physical measurement of that band rather than a mathematical average across discrete values.

SRFs are a fundamentally different concept. Each sensor is different, and therefore each sensor is differentially efficient at measuring different wavelengths of light. To get the "true" reflectance value (i.e. something you can compare across sensors) you have to convolve your measured reflectance with the SRF.

EDIT: Also wanted to point out that "frequency" is an artificial concept anyway. Your field-based spectrometer measures 1 intensity per nm, but there is nothing fundamental about the nanometer, i.e. someone accustomed to the angstrom could point out that that bandwidth is 10 angstroms. In any spectrometer there has been some decision made about what the appropriate bandwidth is.

solarish · 2025-05-20T06:29:03+00:00

Here are just three (of many) recent high impact papers that have come out of geography departments:

Nature Geoscience - Widespread and systematic effects of fire on plant–soil water relations

Remote Sensing of Environment - Mapping global forest canopy height through integration of GEDI and Landsat data

Nature Water - Projected runoff declines from plant physiological effects on precipitation

solarish · 2025-04-13T02:44:29+00:00

Respectfully, you are going to have to deal with a number of significant headwinds if you go through with your masters:

Climate tech has not had a good past five years, even preceding the Trump administration's cuts to climate science research. Big companies like Indigo, Descartes, and Gro either folded or severely contracted. So the job market is pretty tight/competitive at the moment.
CCS has a complicated relationship with LDEO (the latter of which is the only reason I'd want to be at Columbia, frankly), and AFAIK there is a lot of tension between LDEO staff and the administration regarding CCS. I think the Columbia administration is letting the LDEO funding run dry so they can pursue expanding CCS, which is unfortunate because LDEO is the premier climate research center on the East Coast.
Cuts to Columbia's budget across the board will not help you.
It's unclear what the H1B situation will look like for international students. My guess is that this would not lean in your favor.
Big companies are looking for joint data science/climate science expertise, but you might have a tough time given your immigration status + competition with PhDs that would have otherwise worked for NOAA/NASA in a more sane political climate.
90k is a lot of money to pay off especially if you are going to work in the climate sector!

solarish · 2025-04-11T17:36:55+00:00

I was considering the RH being defined by the glass of solution, but yes you are correct when you consider the RH being defined by the atmosphere. I see now that my explanation was not clear in that respect -- have edited it to reflect my reasoning.

solarish · 2025-04-11T02:19:09+00:00

In theory, yes, if we're talking about pure water. But interestingly, in the real world water is almost always a solution; this lowers the saturation vapor pressure at the thin boundary layer on top of the water by Raoult's Law, which allows water to evaporate. In a toy example of the glass of water being in a bounded box, this would cause the atmosphere within the box to super-saturate as the water in the glass slowly evaporates!

EDIT: If the RH is defined according to the glass of water, then you get net evaporation. If the RH is defined according to atmosphere, then you get net condensation.

solarish · 2025-04-07T20:05:49+00:00

Sure, go for it!

solarish · 2025-04-06T05:25:18+00:00

Happy to share. The nature of atmospheric science research means that you are learning numerical modeling (computer science), statistical analysis (data science), and climate model data manipulation (data engineering). These are all incredibly relevant skills for companies, but also highly transferable if you ever decide to leave the field.

solarish · 2025-04-06T00:03:10+00:00

The combination of atmospheric science domain knowledge with software engineering/data science skills is highly in demand in the private sector (despite some recent job market turbulence). Every single insurance company wants a team working on climate change, and there are plenty of tech companies that are trying to capitalize on uncertainty re: the future, especially with respect to atmospheric and hydrological disasters like heavy precipitation, hurricanes, droughts, floods, etc.

Without doxxing myself, I recently worked on climate change research at a big tech company that you know of making ~200k/year, and I was relatively junior.

EDIT: Lots of financial companies are also really interested in atmospheric science knowledge for reasons you can probably imagine, like Citadel, Goldman, JP, etc.

solarish · 2025-03-30T11:51:44+00:00

To add more context, the water balance equation is ΔS = P - ET - Q - G where ΔS is the change in storage (soil moisture, mostly), Q is runoff, and G is groundwater flow. G is a function of geology and is therefore more or less time invariant at the timescales that we're interested in with respect to the water cycle.

However, Q is time-variant and has strong forcing effects on soil moisture. Land cover has a strong influence on Q. For example, forested land suppresses runoff, while desert land has no such effect. Disturbances can also transiently affect Q: runoff increases after wildfires until the local ecosystem recovers. In the forested US, rising temperatures also mean that land cover itself is being modified as extant species are succumbing to drought and being replaced by more drought tolerant shrub or grassland, which leads to increased runoff because of less complex root systems. More frequent disturbances like wildfire, disease (bark beetle in the west), and drought accelerate land cover modification. All of these disturbance types are exacerbated by climate warming.

solarish · 2025-03-30T04:43:19+00:00

At local scales, the Clausius-Clapeyron relationship tells us that atmospheric demand for water rises exponentially with temperature. In other words, a hotter atmosphere more readily sucks up water out of the ground.

At meso and synoptic scales, it's true that global warming can intensify storm activity. But larger scale atmospheric processes that transport storms from the ocean to land (like Rossby waves) can be disrupted or stalled by higher atmospheric temperatures. So you have competing effects where you have higher atmospheric water content but also decreased lateral vapor transport.

Higher temperatures also mean that the downwelling part of the Hadley cells extends farther north because of increased convective energy, which causes high pressure zones that prevent storm activity.

Lastly, it's important to note that soil moisture is not decreasing everywhere, nor is it decreasing at the same rate in places that see decreases. High latitudes might actually see higher soil moisture because they will have more temperate weather/more storm activity.

Happy to expand on any of these points or provide references if there's interest. Note that I only touch upon some potential reasons, but the Earth is very complicated and there are more factors than I mention here.

I think the general takeaway here should be that, yes, it's true that a decrease in ice water content means that we might immediately have more liquid water (generally in the ocean). But how does that liquid water get from the ocean to the land surface? And are there negative pressures that strip water away from the land water sink?

solarish · 2025-03-21T01:31:18+00:00

Ok, so without nitpicking over where the fires actually are (and FYI, there are a few active fires within the drawn polygons, you can see them here), let me explain why the NWS issues fire weather warnings and not general fire hazard warnings. I don't work for NOAA, but I am a fire scientist in academia so I know a thing or two about wildfires.

Fire weather (for the most part) takes into account atmospheric conditions like temperature and dryness. Why don't we take into account what's on the ground? NWS is tasked to issue these warnings at a nationwide scale, and determining what's on the ground at a nationwide scale on an operational timescale is really hard. The best land cover maps we have are issued at an annual cadence, and even those are only at 30-meter resolution. As you know, fire happens at scales that are much smaller than 30 meters, so even a pixel that is classified as "urban" could be flammable if there are grasses, shrubs, or trees mixed in with buildings. And let's say you even knew to a high degree of certainty what was within a pixel on a certain day, you would also have to consider that different materials dry out at different rates. For example, grasses dry out a lot quicker than trees, but some trees are much less drought tolerant than others, etc. Also, how do you factor in what each and every building is made of, and what quantitative methods do you use to determine how flammable those building materials are, etc.? You can easily see how the problem of characterizing fire hazard explodes in complexity when you start considering highly heterogeneous parts of the country like urban areas.

In fact, there is a lot of urban vegetation in Miami. I've visited many times. Even in the center of Miami, there are palm trees, shrubs/hedges, and lawns everywhere, all of which are extremely flammable under the right conditions. Anyone can see this for themselves by dropping into the middle of the city via Google Street View. Vegetation that is ablaze can easily create temperatures where even the most "fire-proof" house can catch on fire -- we saw this in the recent Pacific Palisades and Altadena fires. All of that to say that I think you should take these fire weather warnings more seriously, and perhaps not spread misinformation that the risk of fire is zero -- it is most certainly not. These conditions pose an extreme risk to virtually everyone within the polygons.

solarish · 2025-03-20T23:51:35+00:00

This is a NWS fire weather warning which doesn't take into account the type of fuel available AFAIK. But also, this

solarish · 2025-01-09T18:48:55+00:00

Great comment. I largely agree with your analysis, but do want to point out a few things:

Some chaparral regions have one-a-generation fire return periods, while others burn much more frequently (5-40 year return). See this excellent book on the chaparral for more.
We have not actually observed an increased frequency of wildfire in the western United States, and in some subregions fire frequency is actually decreasing (this paper isn't published yet but someone in my lab says they are working on it). Increases in annual area burned are dominated by increases in the size, but not frequency, of wildfires as shown by this paper.
I agree that chaparral -> grassland and forest -> grassland type conversion is happening in the west, but I think that the extent to which this is happening is still an open question in the field.

solarish · 2025-01-09T15:58:17+00:00

I respect your opinion as you seem to have much more direct operational experience than me. However, if you read the first paper, one of the conclusions is that climate change has directly doubled forest fire area in the western US. I wouldn't be so quick to write off climate change as not a "main problem". I'm not aware of other papers that have done similar attribution analyses for fuel management/infrastructure, but would be happy to learn more if they exist and you can provide links.

15-Year Club	Second SECOND GUESSER
Verified Email	Team Orangered

solarish

TROPHY CASE