1. Ecohydrology of Dry Ecosystems: Rainfall in Central Kenya
Kathleen Ryan ‘14
Caylor Ecohydrology Lab
Mpala Research Center

2. Caylor Ecohydrology Lab
“…seeks to develop improved insight into the way that land use and climate change are interacting to affect the hydrological dynamics and ecological resilience of global drylands.”
Purpose of the caylor ecohydroloy labat mRC (mpala resaerch center) is to develop an idea about how global climate change and local land use is affecting the hydrological dynamics of thekenyan dryland ecosystem. Things the lab is currently looking closely at is how rainfall, water vapor, vegetation, and more broadly, how ecological resiliance will by affected.
Mpala Research Center, Central Kenya
Dry Ecosystem

3. Rainfall How much rain is falling? Where is it coming from?
What is the isotopic
signature of the rain?
So in the caylor lab, there are always a few experiments going on addressing these issues. The two other interns and myself where each given the reigns to an experiment or set of experiments that examined some aspect of the hydrological cycle of the system. I was addressing Rainfall. Specifically, I tried to find out more about, HOW MUCH rain was currently and had been falling in and around Mpala for about the last 40 years, where the rainy air parcels where coming from, and how the path of the rainy air parcel affected the amount of heavy hydrogen and heavy oxygen in the rain. This is called the isotopic signature of the rain.

4. How much rainfall?
Is the amount or pattern of rainfall changing over time?
Calibration
Rain database
First thing to figure out: is amount of rfall changing over time? This will give us a hint about how recent land use may be affecting weather in the region, and how global climate change may be affecting this part of kenya specifically.
Check the existing rain gauges and make sure they are collecting data properly, note major sources of error, and correct if possible. Find out more about data sources, so can interpret data more accurately. Then if possible minimize sources of error. After this, typing up all paper data into workable database, that includes information about data source etc…

5. Where is it coming from? HYSPLIT Region of origin? Land Traversed?
Earlier rains?
Geological features?
(Hybrid Single Particle Lagrangian Integrates Trajectory Model) . NOAA program developed by their Air Resource Laboratory, which can take point data about an air parcel (long, lat, time) and show user a trajectory of that air parcels movement BACKWARDS in time for over ten days, along with the meteorological data assocated with the air parcel. Using this data, tried to fogire out, over the ten days before the storm, what percentage of the total distance traveled by the air parcel was over land, over sea. How much did the air parcel rainout before arriveing at Mpala, and what giological features did the air parccel interact with to lead to the resultant trajectory/rainfall etc…

6. Using this data and some other Text files attached to the images, we started analyzing how aspects of the rain air parcel affected the istopic signature of the rain sample associated with the tracked air parcel.

7. Connections Solar Radiation
Distance air parcel traveled over land & elevation of land
Isotopic signature can be used to tag and track water/vapor from different sources
Solar radiation affects isotopic signature. Higher levels of radiation, heavy the water was. There was a significant relationship between the rain sample isotope value and the amount of solar radiation the air mass received along the trajectory. Modeling the residuals of this relationship with the distance it travelled over land as well as the mean elevation of that land, led to a fairly good first-order model of the isotope values.

8. Conclusions …I could get used to this.
This is a picture of us on a little weekend trip. Our equivalent of hitting the mall for a good time. Not True! But this was really only possible b.c. we were in the field. I really love fieldwork! Theoretically though “field work is for me!” this summer proved it, while I am always having fun at school and in princeton, I really think I have had my most fun since coming to princeton where out there in the sun, measuring stuff, getting frsturating, having eueka moments, and really just both exploring and enjoying the natural world around us. So as a result… I really hoep to continue pursuing a career in fieldwork, preferably fieldwork in african ecosystems.
…I could get used to this.

9. Thank you for your guidance and support.
Dr. Soderberg
Molly O’Connor
Dr. Caylor

10. Alice Suh & Hannah Safford
We had a fantastic time!
Alice Suh & Hannah Safford
Dr. Rubenstein
John Mitonga
Ekoma Akuwam