• 6 min read

Soils Animated: Part 1

Animation is a powerful tool for demonstrating scientific concepts. It is engaging, simplifies abstract ideas, and makes them accessible to a wide audience.

In hydrology, one of the most simple yet elegant conceptualization of soil-water dynamics is the soil moisture loss function, a model developed by Laio et al. (2001) and Rodriguez-Iturbe et al. (1999). This model abstract complex soil processes at the field scale into a few key variables, providing ecohydrologists with a powerful 'toy model' for conducting a variety of interesting experiments. For example, Entekhabi and Rodriguez-Iturbe (1994) explored the impacts of spatio-temporal aggregation on characterizing heterogeneity of soil moisture dynamics. D'Odorico and Porporato (2004) used it to explain soil moisture seasonality.

In this blog post, I'll animate this soil dynamics model, with Part 1 focusing on the basic concepts. Animations in this blog post will illustrate how hydrologists conceptualize the soil processes happening just above and beneath our feet, while also exploring how these processes unfolds across different conceptual spaces.

  • 9 min read

The Technical side of AGU 2024: What happened and where are we going

Two weeks ago, the American Geophysical Union (AGU) hosted its annual fall meeting in Washington, D.C., with over 25,000 attendees from 100+ countries present to share their research. For those reading who have not been, nor heard of AGU, there are four major themes present:

  • Earth's subsurface
  • Earth's surface
  • The atmosphere
  • Space

Among these four themes, there are several sections, and within each section there are many sessions corresponding to a research topic proposed by a group of scientists. Generally, most scientists submit one abstract to their field of study, and rarely, a second to a different section. At the conference research conversations occurred at posters, sessions, and oddly timed coffee hours during the lulls in programming (had to get my yearly zinger at AGU's coffee policy). Now that my brain, and feet from the 20,000 daily steps, have recovered, I want to write about my most significant takeaway from the week and where I predict things will be headed next year.

  • 10 min read

Hydrology is flat, and its buckets all the way down!

For some reason, much of my recent work keeps coming back to buckets, and re-thinking the conceptualization of natural hydrologic systems as buckets. I am generally sick of talking about buckets. I'm hoping that this post is my farewell to thinking about buckets, at least for a while.

Sir Edmond Leakybucket

When I was first learning differential equations the professor told us a silly story about Sir Edmond LeakingBucket, some ol' timey English royal who had to drink his ale quickly because his ale bucket leaked. I went on to study hydrology, so I've had to think about Sir Edmond for the past fiteen years. I can't escape him. Sometimes he mixes two kinds of ales together, sometimes his ale bucket is more complicated or simpler, but he is always losing his ale. Poor guy. Sir Edmond and his bucket do two important things: 1) gives nice differential equation examples, but more importantly for hydrology 2) Leaking buckets are a primary conceptualization for hydrologic processes.

A simple differential equation for the ale level in Sir Edmond's bucket is:

\[ \frac{dh}{dt} = -k \sqrt{h} \]

Where \(h(t)\) is the ale at time \(t\), k is a proportionality constant that governs the rate of outflow. Its solution through seperation of variables is:

\[ h(t) = \left(\sqrt{h_0} - \frac{k}{2}t\right)^2 \]

Where \(h_0\) is the initial ale level in the bucket at time \(t = 0\). This gives us the opportunity to track volumes of ale through this bucket, and match the fluxes from buckets with data collected on real-world hydrological systesm. This is, in a nutshell, the field of computational hydrology, we just need to dress up and add complications to this bucket, and off we go.