light

The last year of DLI with weekly averages

A previous post showed photosynthetically active radiation (PAR) data in units of daily totals—the daily light integral (DLI). That post included a chart with a locally smoothed regression line through it.

Worldwide agroclimatology data, PAR, shade, and grass

I’ve been using the NASA POWER agroclimatology data for a few projects. I get the data using the convenient nasapower R package by Adam Sparks. There is also a web-based map data access viewer.

Morning shade looks like this

The PPFD (photosynthetic photon flux density) every 5 minutes for a day, week, month, and year at Corvallis looks like this. I’m not so interested in the PPFD when the temperatures are too cold or too hot for photosynthesis.

PAR looks like this

Photosynthetically active radiation (PAR) provides the energy for plants to grow. Unlike temperature or precipitation data, which are readily available, it is less common to see the numbers or charts for PAR.

Northern Virginia sunlight in 2018 compared to previous years

Sean Heath wrote with this question: “do you or anyone else know of data being tracked for sunlight or cloud cover? Specifically how much sunlight did Northern VA receive this year with all the rain and cloud cover?

Four reasons zoysia should be a poor choice for California

I’ve been asked about zoysia suitability for California, particularly northern parts of California, many times. Every time, I give the same answer. In such a relatively cool climate, and in such a relatively sunny and dry climate, Cynodon seems like a much better choice.

High resolution DLI maps of the United States

James Faust and Joanne Logan wrote a review of daily light integral (DLI) in the September issue of HortScience. They have also prepared high resolution maps of the United States. If you click on a location on the map, a table and chart will display with the average annual and monthly DLI.

Turf stories as Twitter Moments

I’ve gathered some collections of tweets into moments for easy viewing in sequence. I previously arranged these on Storify, but that service has shut down. Here’s a quick description of these moments.

Is morning sun the most important for turf? It depends.

I used Storify to string together some related tweets and images over the past few years. That service is shutting down. I’ve moved a “story” about light, shade, and time of day to this Twitter moment.

"I really wish that I could hear this presentation"

That’s what Jon Scott wrote to me on October 7, 2014, after I shared the slides from my shade talk at the Northwest Turfgrass Association conference. We’ve been having a back and forth about this ever since.