Search Results for: parameterization

Boundary Layer Clouds: IPCC Bowdlerizes Bony

As we’ve discussed before (and is well known), clouds are the greatest source of uncertainty in climate sensitivity. Low-level (“boundary layer”) tropical clouds have been shown to be the largest source of inter-model difference among GCMs. Clouds have been known to be problematic for GCMs since at least the Charney Report in 1979. Given the […]

Curry Reviews Jablonowski and Williamson

Jablonowski and Williamson is here. Judith’s review follows.

Hansen in Antarctica

Hansen et al 1988 noted very sensibly that there were radically different approaches to some physical problems in GCMs and looked forward to the “real world laboratory in the 1990s” providing empirical information on these conundrums. One such conundrum were temperatures offshore Antarctica. They noted that their model showed a strong warming trend in sea […]

From Lacis et al 1981 to Archer Modtran

In several recent posts, we’ve been reviewing the provenance of the radiative forcing estimate of about 4 wm-2 and the logarithmic form for estimating climate response to increased CO2 levels. This has led on the one hand to several primary references, including Lacis et al 1981 and, on the other hand, to references to realclimate […]

AR4: "Now-Classic" Results on Cloud Uncertainty are "Unsettling"

AR4 (chapter 1 on the History of Climate Science) contains the remarkable statement: The strong effect of cloud processes on climate model sensitivities to greenhouse gases was emphasized further through a now-classic set of General Circulation Model (GCM) experiments, carried out by Senior and Mitchell (1993). They produced global average surface temperature changes (due to […]

James Annan on 2.5 deg C

I’ve been seeking an engineering-quality exposition of how 2.5 deg C is derived from doubled CO2 for some time. I posted up Gerry North’s suggestion here , which was an interesting article but hardly a solution to the question. I’ve noted that Ramanathan and the Charney Report in the 1970s discuss the topic, but these […]

Vecchi and Soden

Here is Judith Curry’s review.

Review Comments on the "IPCC Test"

In a recent post, I’ve indicated that IPCC authors seems to have invented a “test” for long-term persistence that is nowhere attested in any statistical literature and, if I’ve interpreted what they’ve done correctly, appears to be a useless test. Jean S and I have made a few references to the Review Comments on the […]

Water Vapor Feedback

In response to an inquiry to Scott Saleska, Dan Kirk-Davidoff, a prominent expert in the field, has sent the following suggestions: Soden and Held 2006, An Assessment of Climate Feedbacks in Coupled Ocean—Atmosphere Models, J. Climate 19:3354, DOI: 10.1175/JCLI3799.1 reviews the relative role of various feedbacks in the IPCC AR4 runs. Held and Soden, “Water […]

Feedback in Collins et al 2006

On a couple of occasions, I’ve noted that near infrared water vapor parameterizations in HITRAN-1996 were incorrect and wondered about what the impact of these changes would have been on a non-retuned GCM. It looks like Collins et al JGR 2006 have done something like that – implementing HITRAN changes up to 2003. Unfortunately, they […]