climate, prohibiting straightforward use of correlation lags to believed to cause a net increase in atmospheric concentrations of. GHGs, implying a on the existence of a significant time lag of CO2 behind either .. program Grant NA08OAR/CAMEO, by the Sugihara Family Trust, the Deutsche. The dominant C–Q relationships of the water variables in the study area reflect that results indicate coupled transfer of sediments and solute in the area at lag ≥ 0. partly supported by the Education Trust Fund/Obafemi Awolowo University, Ile-Ife, Estimating mean residence time of karst groundwater in mountainous. The relation of time of concentration (Tc) and lag (L). 15–4 to the dimensionless unit hydrograph. Figure 15–4. Velocity versus slope for shallow.
Climate Science Glossary
I have an article from Science magazine which I will put into the record at the appropriate time that explains that historically, a rise in CO2 concentrations did not precede a rise in temperatures, but actually lagged temperature by to 1, years. CO2 levels went up after the temperature rose. The temperature appears to drive CO2, not vice versa.
On this point, Mr. This subject has been very well addressed in numerous places. Indeed, guest contributor Jeff Severinghaus addressed this in one of our very first RealClimate postsway back in Still, the question does keep coming up, and Jeff recently received a letter asking about this. His exchange with the letter writer is reproduced in full at the end of this post. Below is my own take on the subject.
On historical timescales, CO2 has definitely led, not lagged, temperature. We know why CO2 is increasing now, and the direct radiative effects of CO2 on climate have been known for more than years. In the absence of human intervention CO2 does rise and fall over time, due to exchanges of carbon among the biosphere, atmosphere, and ocean and, on the very longest timescales, the lithosphere i.
The rates of those exchanges are now being completely overwhelmed by the rate at which we are extracting carbon from the latter set of reservoirs and converting it to atmospheric CO2.
No discovery made with ice cores is going to change those basic facts. Second, the idea that there might be a lag of CO2 concentrations behind temperature change during glacial-interglacial climate changes is hardly new to the climate science community.
Indeed, Claude Lorius, Jim Hansen and others essentially predicted this finding fully 17 years ago, in a landmark paper that addressed the cause of temperature change observed in Antarctic ice core records, well before the data showed that CO2 might lag temperature.
In that paper Lorius et al. Thus, both CO2 and ice volume should lag temperature somewhat, depending on the characteristic response times of these different components of the climate system. Ice volume should lag temperature by about 10, years, due to the relatively long time period required to grow or shrink ice sheets.
Several recent papers have indeed established that there is lag of CO2 behind temperature.
Climate time lag
Still, the best published calculations do show values similar to those quoted by Barton presumably, taken from this paper by Monnin et al. But the calculations can only be done well when the temperature change is large, notably at glacial terminations the gradual change from cold glacial climate to warm interglacial climate. So it is not as if the temperature increase has already ended when CO2 starts to rise. Rather, they go very much hand in hand, with the temperature continuing to rise as the the CO2 goes up.
In other words, CO2 acts as an amplifier, just as Lorius, Hansen and colleagues suggested. The following graph illustrates the different resulting outflows for each design storm. The year storm had the highest peak and volume the area under the curve and the 5 year storm had the lowest. They each had the same duration time.
The following hydrographs resulted. The higher curve numbers result in a larger amount of runoff and therefore a higher peak flow and flow volume. The curve number of 93 would be representative of the Shoal Creek watershed because of it being an urban watershed with substantial development. The curve number of 77 would be representative of a undeveloped watershed with good soil infiltration and slower overland flow velocity.
Note how the peak of CN77 is much lower and the curve is flattened out. A smaller lag time smaller time of concentration results in a higher peak flow over a smaller time interval. The peak flow occurs very close the time of peak rainfall where the curve is almost vertical. As the time of concentration is decreased the peak flow and the peak rainfall intensity get closer together. The graph below shows the outflow hydrograph and the accumulated rain total for the period.
Note the rainfall that occurred the day before the flood event. It was enough rain to saturate the soil and cause a higher proportion of the rainfall that occurred the next day to runoff. In terms of the HEC1 model this situation would cause the Curve Number to be higher due to antecedent rain. One consequence of a higher curve number is that the time of concentration is lower as can be seen in the equation for time of concentration above.
The graph below is the results of my first calculations of the time of concentration for the model using two different values for the CN.
The two model hydrographs are plotted with the actual Shoal Creek hydrograph. The design storms are year storms, which ,according to the data, represents the Memorial Day storm. The reason the peak flow for the model is lower than the actual peak flow is the time of concentration was too high.
How long does the climate take to return to equilibrium? The lag is a function of climate sensitivity. The more sensitive climate is, the longer the lag. How would climate have responded to the solar levels maxing out in the 50's?
WMS:Lag Time and Time of Concentration - XMS Wiki
For the next few decades after the 50's, the radiative imbalance would've gradually decreased until the climate reached radiative equilibrium around the late 80's give or take a decade. So how has our planet's radiative imbalance evolved over the latter 20th century? There is no indication that the climate is heading towards equilibrium - quite the contrary. This is confirmed by satellite measurements of energy flux at the top of the atmosphere: Global ocean heat storage blue against global net flux anomalies Wong The climate is not heading towards equilibrium.