157 lines
10 KiB
HTML
157 lines
10 KiB
HTML
<!DOCTYPE html>
|
||
<html lang="en">
|
||
<head>
|
||
<meta charset="UTF-8" />
|
||
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
|
||
<title>SunSoak & the science · SunScope</title>
|
||
<meta name="description" content="How the SunSoak index works — built on the UTCI standard with a rain and snow penalty, a Solar Model for your surroundings (forest, alpine, beach, river, desert, open water), and full mean radiant temperature." />
|
||
<meta name="robots" content="index, follow" />
|
||
<link rel="canonical" href="https://sunscope.net/sunsoak.html" />
|
||
|
||
<meta property="og:title" content="SunSoak & the science · SunScope" />
|
||
<meta property="og:description" content="What SunSoak is and how it layers a precipitation penalty, a Solar Model for your surroundings, and mean radiant temperature on top of UTCI." />
|
||
<meta property="og:url" content="https://sunscope.net/sunsoak.html" />
|
||
<meta property="og:type" content="article" />
|
||
<meta property="og:image" content="https://sunscope.net/og-image.png" />
|
||
<meta name="twitter:card" content="summary_large_image" />
|
||
<meta name="twitter:title" content="SunSoak & the science · SunScope" />
|
||
<meta name="twitter:description" content="What SunSoak is and how it layers a precipitation penalty, a Solar Model for your surroundings, and mean radiant temperature on top of UTCI." />
|
||
<meta name="twitter:image" content="https://sunscope.net/og-image.png" />
|
||
|
||
<link rel="icon" type="image/svg+xml" href="./favicon.svg" />
|
||
<link rel="stylesheet" href="./assets/about.css?v=15b">
|
||
|
||
<script type="application/ld+json">
|
||
{
|
||
"@context": "https://schema.org",
|
||
"@type": "Article",
|
||
"headline": "SunSoak & the science",
|
||
"about": "The SunSoak thermal comfort index and how it extends the UTCI standard.",
|
||
"publisher": { "@type": "Organization", "name": "SunScope", "url": "https://sunscope.net" },
|
||
"mainEntityOfPage": "https://sunscope.net/sunsoak.html"
|
||
}
|
||
</script>
|
||
</head>
|
||
<body>
|
||
|
||
<header id="site-nav">
|
||
<div class="nav-overlay" onclick="toggleNav(false)"></div>
|
||
<a href="./index.html" class="nav-logo">
|
||
<span class="nav-logo-wordmark"><span class="nav-logo-sun">Sun</span><svg class="nav-logo-icon" viewBox="0 0 174 173" aria-hidden="true" style="fill-rule:evenodd;clip-rule:evenodd;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:1.5;"><g transform="matrix(0.986226,0,0,0.986226,-585.724252,-110.041209)"><clipPath id="ss-clip-ss"><circle cx="681.9838" cy="199.4502" r="83.2987"/></clipPath><g clip-path="url(#ss-clip-ss)"><g transform="matrix(0.948836,0,0,0.948836,19.748711,-12.198562)"><path d="M666.992,233.0768C666.3949,230.6581 666.1785,228.6317 666.1785,226.0296C666.1785,208.6786 680.2653,194.5919 697.6163,194.5919C714.9672,194.5919 729.054,208.6786 729.054,226.0296C729.054,228.4125 728.9892,230.9346 728.4859,233.1663" fill="#f4b047" stroke="#f4b047" stroke-width="7.48" stroke-linecap="round"/></g><g transform="matrix(0.520349,0,0,0.520349,304.727514,54.521964)"><path d="M724.9315,291.8131C777.359,291.8131 826.5862,305.6245 869.1698,329.8044" fill="none" stroke="currentColor" stroke-width="13.64"/></g><g transform="matrix(0.520349,0,0,0.520349,304.727514,54.521964)"><path d="M580.8436,329.719C623.3927,305.592 672.5657,291.8131 724.9315,291.8131" fill="none" stroke="currentColor" stroke-width="13.64"/></g></g><circle cx="681.9838" cy="199.4502" r="83.2987" fill="none" stroke="currentColor" stroke-width="9.13"/></g></svg><span class="nav-logo-scope">Scope</span></span>
|
||
<span class="nav-logo-tag">See the world the way your skin does.</span>
|
||
</a>
|
||
<div class="nav-links" id="nav-drawer">
|
||
<a href="./index.html">Forecast</a>
|
||
<div class="nav-dropdown">
|
||
<a href="./about.html" class="nav-dropdown-toggle active">About<span class="caret">▾</span></a>
|
||
<div class="nav-dropdown-menu">
|
||
<a href="./about.html">Overview</a>
|
||
<a href="./sunsoak.html" class="active">SunSoak & the science</a>
|
||
<a href="./profiles.html">Forecast profiles</a>
|
||
<a href="./columns.html">Column reference</a>
|
||
<a href="./temperatures.html">Derived temperatures</a>
|
||
<a href="./features.html">On-screen features</a>
|
||
<a href="./stress-bands.html">Stress bands</a>
|
||
</div>
|
||
</div>
|
||
<a href="./faq.html">FAQ</a>
|
||
<div class="nav-dropdown nav-dropdown--right">
|
||
<a href="./dashboard.html" class="nav-dropdown-toggle">Account<span class="caret">▾</span></a>
|
||
<div class="nav-dropdown-menu">
|
||
<a href="./dashboard.html">Dashboard</a>
|
||
<a id="nav-account-subscription" href="https://buy.stripe.com/9B63cw7vl8k15Ei9DQd7q00" target="_blank" rel="noopener noreferrer">Subscription</a>
|
||
<a id="nav-account-signinout" href="./dashboard.html">Sign in</a>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<button class="utci-burger" aria-label="Open menu" aria-expanded="false" id="burger-btn" onclick="toggleNav()">
|
||
<span></span><span></span><span></span>
|
||
</button>
|
||
</header>
|
||
<script>
|
||
function toggleNav(force) {
|
||
const nav = document.getElementById('site-nav');
|
||
const drawer = document.getElementById('nav-drawer');
|
||
const btn = document.getElementById('burger-btn');
|
||
const open = force !== undefined ? force : !nav.classList.contains('nav-open');
|
||
nav.classList.toggle('nav-open', open);
|
||
drawer.classList.toggle('is-open', open);
|
||
btn.setAttribute('aria-expanded', open ? 'true' : 'false');
|
||
}
|
||
</script>
|
||
<script src="./assets/js/nav-account.js" defer></script>
|
||
|
||
<main>
|
||
<h1>SunSoak & the science</h1>
|
||
<p class="tagline">The honest felt-temperature number, and what goes into it.</p>
|
||
|
||
<h2>What is SunSoak?</h2>
|
||
<p>
|
||
Standard UTCI is calculated assuming open, unshaded conditions with no precipitation — it tells
|
||
you how the wind and sun affect your body, but not the full picture of where you actually are or
|
||
what the weather is actively doing to you. <strong>SunSoak</strong> fills those gaps with three
|
||
layers of original calculation stacked on top of the UTCI foundation.
|
||
</p>
|
||
|
||
<h2>The precipitation penalty</h2>
|
||
<p>
|
||
Rain and snow are not in UTCI. The soak-factor formula adds an original penalty based on rain
|
||
intensity, snowfall rate, and wind speed — reflecting the extra chill of wet clothing and skin.
|
||
Light drizzle (under 1 mm/hr) reduces the felt temperature by roughly 1–2 °C. Heavy rain combined
|
||
with strong wind can push it down by 7–8 °C. Snowfall carries an additional penalty on top.
|
||
</p>
|
||
|
||
<h2>The Solar Model</h2>
|
||
<p>
|
||
UTCI assumes you are standing in the open. SunScope's <strong>Solar Model</strong> adjusts the
|
||
solar radiation load and air temperature for the place you actually are, selectable from a
|
||
dropdown on the SunSoak column. There are eight models:
|
||
</p>
|
||
<table class="stress-table">
|
||
<thead>
|
||
<tr><th>Solar Model</th><th>What it does to the felt temperature</th></tr>
|
||
</thead>
|
||
<tbody>
|
||
<tr><td><strong>Grass / Open Field</strong></td><td>The UTCI default — full sun exposure over natural ground, no adjustment.</td></tr>
|
||
<tr><td><strong>Town / City</strong></td><td>Urban heat island raises air temp ~2–3 °C; building canyons cut direct and diffuse solar, with reflections partly offsetting the reduced sky view.</td></tr>
|
||
<tr><td><strong>Beach / Lakeside</strong></td><td>Water and sand reflect extra radiation back at you, increasing the effective solar load and UV dose.</td></tr>
|
||
<tr><td><strong>River / Riverbank</strong></td><td>Canopy and valley walls cut direct sun; evaporative cooling from the water lowers apparent air temperature.</td></tr>
|
||
<tr><td><strong>Forest / Woodland</strong></td><td>Canopy reduces direct radiation by around 85%; air temperature is adjusted down for evapotranspiration cooling.</td></tr>
|
||
<tr><td><strong>Open Water</strong></td><td>Full solar exposure with additional reflection off the water surface, no shade or shelter, and no ground-heat contribution.</td></tr>
|
||
<tr><td><strong>High Altitude / Alpine</strong></td><td>Thinner atmosphere at ~2,000 m enhances radiation by around 15%, adjusted for exposed ridge conditions.</td></tr>
|
||
<tr><td><strong>Desert / Arid</strong></td><td>Extreme radiation load from high-albedo sand and bare ground, with ground-level heat significantly raising the felt temperature.</td></tr>
|
||
</tbody>
|
||
</table>
|
||
<p>
|
||
Selecting a Place, Activity, or Work profile automatically sets the most appropriate Solar Model
|
||
for that context — but you can always override it manually. The chosen model also drives the
|
||
<strong>Shade Air</strong> column, which estimates the air temperature sitting in that model's
|
||
typical shade (see the <a href="./columns.html">column reference</a>).
|
||
</p>
|
||
|
||
<h2>Mean radiant temperature</h2>
|
||
<p>
|
||
The full radiant heat load from surrounding surfaces — ground, walls, sky, and direct sun — is
|
||
calculated as Mean Radiant Temperature (Tmrt) and fed into the UTCI polynomial. On a sunny day
|
||
this alone can add 20–30 °C to the felt temperature compared to a shaded reading. It is why
|
||
stepping into shade feels so much cooler even though the air temperature hasn't changed.
|
||
</p>
|
||
|
||
<h2>Reading the result</h2>
|
||
<p>
|
||
The combined SunSoak value is colour-coded into thermal stress bands so you can read conditions
|
||
at a glance — see <a href="./stress-bands.html">reading the stress bands</a>. For a plain-language
|
||
description of every column that feeds into or sits alongside SunSoak, see the
|
||
<a href="./columns.html">column reference</a>.
|
||
</p>
|
||
|
||
</main>
|
||
|
||
<footer>
|
||
© 2026 <a href="https://fraxle.net" target="_blank" rel="noopener noreferrer">Fraxle.NET</a> · <a href="./index.html">Forecast</a> · <a href="./about.html">About</a> · <a href="./faq.html">FAQ</a>
|
||
· <a href="./dashboard.html">Dashboard</a> · <a href="https://billing.stripe.com/p/login/9B63cw7vl8k15Ei9DQd7q00" target="_blank" rel="noopener noreferrer">Account</a> · Data: <a href="https://open-meteo.com/" target="_blank" rel="noopener noreferrer">Open-Meteo</a> · UTCI: <a href="https://utci.org/" target="_blank" rel="noopener noreferrer">Bröde 2012</a>
|
||
</footer>
|
||
|
||
</body>
|
||
</html>
|