Category: Geography

2017 Will Be One of Those Harvests You Never Forget

Posted on by LHP

Saturday evening we attended a “Release Dinner” for one of our favorite wineries up in Napa. That’s where they roll out the vintage they’ll sell in the upcoming year (in this case, the 2014 vintage), sip some samples of the vintage, and maybe some past vintages, enjoy some food, and hobknob with the owner and the winemaker and the staff and other fans of the winery. They are fun events.

Midway through the evening each of the principals stood up and said a few words. The winemaker, Ricardo Herrera, was third or fourth up, and he said, in his quiet, shy way, that he told his staff and his colleagues that 2017 would be “one of those harvests you never forget.” He was referencing the difficulties they had with the weather, which was warm all summer and featured late rain, and a delicate balancing act. The grapes hadn’t ripened fully due to the odd weather, but the unusually high heat they experienced in September presented the possibility that the fruit might not fully ripen before it was shriveled by the sun. So it was wait and risk a severely reduced yield or harvest early and try to work with under ripe fruit. They decided to wait and risk it, but hedged with some extra irrigation. (They are loathe to do that because they prefer that the vines drive their roots down to find their own water rather than rely on irrigation.) There was a lot of discussion among winemakers and vineyard managers about which course was correct, and not everyone decided to wait. We’ll have to see how the wine turns out to know if Ricardo guessed right. He said he thought we would be rewarded.

Of course when he spoke, Ricardo could not have known about the wildfires that were to sprout a night later, the unforgettable unwinding of the deal he had struck with nature.

Why has the Summer Been So Gloomy?

Posted on by LHP

My explanation of Southern California’s June Gloom didn’t shed much sunlight on why it has become the June-July-August Gloom. Last week the National Weather Service released a brief statement explaining why: cooler than usual waters in the Pacific Ocean and a persistent “upper level trough” in the atmosphere above the coastline. That upper level trough — or low pressure system — has helped keep the air cool. Together, our cooler water and cooler air have prompted the formation of the clouds and fog that creep inland overnight. This combo has also kept monsoonal moisture at bay. So while the American Southwest is enjoying afternoon thunderstorms, Southern California’s mountains and deserts have not.

All that was supposed to have changed this weekend. Temps were up inland and slightly higher here at the beach. And this morning’s bright sunrise, among a handful of fogless dawns this summer, promised a scorcher. But by noon today dense fog had tumbled in from the harbor. If you listen, you can hear the ships’ fog horns booming in the distance, heralding the end of the heatwave that wasn’t.

Places: There’d Be More Butterflies

Posted on by LHP

What’s an Ecoregion?

The WWF, which takes the lead in categorizing and describing such things, tells us that an ecoregion is:

a large area of land or water that contains a geographically distinct assemblage of natural communities that

  1. share a large majority of their species and ecological dynamics;
  2. share similar environmental conditions, and;
  3. interact ecologically in ways that are critical for their long-term persistence.

The WWF recognizes 825 terrestrial ecoregions, 426 freshwater ecoregions and 200 marine ecoregions. From these, the WWF has identified 200 priority ecoregions. The Global 200 are the planet’s most biologically distinct regions; conserving these would preserve the broadest possible diversity of plants and animals. The California coastal sage and chapparal ecoregion is one such ecoregion.

The ecoregion encompasses 14,000 square miles of Southern California and Northern Mexico coastline, as well as the nearby Channel Islands. The Santa Rosa Mountains, northeast of San Diego are included, but the San Jacinto Mountains a bit further north and east are not (they’re part of the California montane chaparral and woodlands, instead). The climate is Mediterranean, which means cool wet winters and hot dry summers. Rainfall ranges between 6 and 20 inches a year.

So. What’s here?

If we weren’t here there’d be lots of coastal and valley oaks, groves of California walnut, lots more sage, of several varieties, coastal grasslands and vernal pools, salt marshes along the coasts and manzanita and toyon up in the foothills. There’d be a lot more California gnatcatchers. There’d be plenty of kangaroo rats, legless lizards and rosy boas. There’d be more butterflies (150-200 different species) and there’d be a bunch more spiders.

We still have all those things — and more, including plenty of endemics* like some of the aforementioned and the horned lizard and the Cactus wren. Out on the islands we have some relicts, too, which are species that are holdovers from long ago. Locoweeds, buckwheats and oaks are relicts out there. The Catalina ironwood used to be everywhere around here, but now it’s only found on Catalina Island. Of course, we’ve tilled under and paved over most of the places those things lived. Just 15% of the ecoregion is intact. The whole ecoregion is practically a relict.

Large swathes of the original habitat are protected within the Camp Pendleton Marine Corps base north of San Diego. The Torrey Pine State Reserve protects one of just two stands of that tree. Other bits of the habitat are intact here and there at parks and reserves in the Santa Monica Mountains and in Riverside County and in stretches of still undeveloped Irvine Company inventory in Orange County. A little bit more has been set aside recently in Crystal Cove State Park, with hiking trails that used to be roads and holiday beach house rentals that used to be homes, more relicts from another time.

——————-
*An endemic species is one that is only found in a particular place and habitat and no place else.

Now I Know: Southern California’s June Gloom

Posted on by LHP

June Gloom is the phrase many Southern Californians use to describe the generally overcast skies that hang over the region in late spring and early summer. The gloom is deepest just after dawn and heaviest near the beaches. But by midday — earlier over points inland — the clouds burn off and the basin’s familiar over-saturated sunlight washes over all. Well, the sunlight washes over all except those of us who live within a mile of the shoreline, where the overcast may linger deep into the afternoon.

The gloom and overcast are a result of the marine layer, which is a kind of temperature inversion layer. Normally, higher air temperatures are found near the ground and cooler temperatures are found aloft. An inversion layer sees this relationship turned upside down: cooler temperatures are found near the surface and warmer temperatures lie above. One effect of an inversion layer is a “capping” of normal convection currents — the rising and falling of air due to thermals — which traps dust and other particles under the inversion layer. LA’s famously bad air quality is partly a result of this meteorological quirk.

Our local inversion layer is generated by the especially chilly waters of the Pacific Ocean. The California Current carries frigid sea water south from the Gulf of Alaska to the tip of Baja. The sea water cools the air above, creating a temperature inversion. If there is enough moisture in the air, and the cooling effect is strong enough, then clouds and fog are generated within the marine layer. Depth of the marine layer is affected by the movement of much larger weather systems in the atmosphere above. High pressure systems squish the marine layer so that only coastal areas lie under the gloom. Low pressure systems allow the marine layer to expand upward and outward; fog along the shore rises and pushes inland.

It’s just after 2:00 pm PDT here in Long Beach, CA, and the sun is just beginning to burn through the clouds above. June Gloom has stretched all the way through July. But when the alternative is thunderstorms and sweltering heat, I don’t think many of the locals mind.

Now I Know: SoCal Thunderstorms

Posted on by LHP

Southern California’s monsoon and thunderstorm season got underway last Monday, and if you were paying attention, you felt it. At dawn the sky above was dull and gray — the so-called June Gloom — but by 10:00 am the marine layer had been beaten back out to sea. High altitude high pressure air had slipped in from the deserts to the east, sending the cooling gloom away. Temperatures have risen steadily since and everyday thunderstorms form over the mountains that ring the Los Angeles basin (such as seen from the beach, here).

Thunderstorms require three things to form: moisture, air instability, and a lifting force.

Moisture can come from oceans or from remnants of hurricanes or other storms.

Air instability occurs when a cool dry pocket of air rests over a warmer, wetter pocket of air; given a sufficient nudge, the warm, moist air will rise.

Lifting force usually comes from heat, whether by temperature differential (uneven heating of the ground, which creates thermals) or by boundaries between pockets of air (warmer air will rise over cooler; the heat differential between drier and wetter air will force the wetter air up; and the outflow boundary, on the edge of a thunderstorm, is cooler than the surrounding air, creating more thunderstorms). Lifting force can also come from topography — wind moving up mountain slopes and through canyons will provide the push the moist air needs to get aloft.

Once aloft, the air rises and cools, condensing its moisture into water droplets, which form clouds. More rising air pushes some droplets still higher, where they continue to cool and grow. Some fall as rain. Some freeze and fall and melt back into rain. Some freeze and fall and stay frozen and fall to the ground as hail.

The high pressure that arrived on Monday gave the thunderstorms two of the three necessary ingredients: air instability and lifting force. Without the marine layer to keep us cool, temperatures began to rise (in Downtown LA it was 75 on Monday, 86 on Tuesday, then 94, then 92, and 93 today). While heat differentials promote thundercloud formation, our topography probably plays a larger role. The Los Angeles basin is ringed with mountains — the San Gabriels to the north, the San Bernardinos to the northeast, the Santa Anas to the southeast. Air moving onshore from the ocean rises up the slopes and through the canyons, pushing warmer, moister air up. Upslope thunderstorms are common in the Rocky Mountains and the Sierra Nevadas and they occur here, too. We also have several convergence zones — regions where breezes, after having diverged around mountains and through canyons, collide and force air upward. One such convergence zone is near Lake Elsinore (the Lake Elsinore Convergence Zone), on the eastern side of the Santa Ana Mountains, where this supercell thunderstorm and funnel cloud was videotaped.

For the third element — moisture — we return to the opening line of this post and that word “monsoon”, which seems out of place when discussing Southern California. The North American, or Arizona, or Southwest monsoon occurs when high pressure moves over the southwest from the south and intense summertime heating of the desert creates rising air and low pressure. The monsoon takes place between June and mid-September. The result is a change in direction of prevailing, low level air flow that brings moisture up from the Gulf of California and the Western Gulf of Mexico. This moisture is then forced up by heat differentials and upslope winds to form into water droplets and clouds and eventually thunderstorms.

Other than that, all I know about our monsoon and thunderstorms is that mid-September is a long way off.